@article {Grilo_2021, title = {Comprehensive Laboratory Measurements Resolving the {LMM} Dielectronic Recombination Satellite Lines in Ne-like Fe xvii Ions}, journal = {The Astrophysical Journal}, volume = {913}, number = {2}, year = {2021}, note = {n/a}, month = {jun}, pages = {140}, publisher = {American Astronomical Society}, abstract = {n/a}, doi = {10.3847/1538-4357/abf737}, url = {https://doi.org/10.3847\%2F1538-4357\%2Fabf737}, author = {Filipe Grilo and Chintan Shah and Steffen K{\~A}{\textonequarter}hn and Ren{\'e} Steinbr{\~A}{\textonequarter}gge and Keisuke Fujii and Jos{\'e} Marques and Ming Feng Gu and Jos{\'e} Paulo Santos and Jos{\'e} R. Crespo L{\'o}pez-Urrutia and Amaro, Pedro} } @article {Krauth_2021, title = {Measuring the $\upalpha$-particle charge radius with muonic helium-4 ions}, journal = {Nature}, volume = {589}, number = {7843}, year = {2021}, note = {n/a}, month = {jan}, pages = {527{\textendash}531}, publisher = {Springer Science and Business Media {LLC}}, abstract = {n/a}, doi = {10.1038/s41586-021-03183-1}, url = {https://doi.org/10.1038\%2Fs41586-021-03183-1}, author = {Krauth, Julian J and Schuhmann, Karsten and Ahmed, Marwan Abdou and Amaro, Fernando D. and Amaro, Pedro and Biraben, Fran{\c c}ois and Chen, Tzu-Ling and Covita, Daniel S. and Dax, Andreas J and Diepold, Marc and Fernandes, Luis M. P. and Franke, Beatrice and Galtier, Sandrine and Gouvea, Andrea L and Johannes G{\~A}{\textparagraph}tzfried and Graf, Thomas and Theodor W. H{\~A}¤nsch and Jens Hartmann and Hildebrandt, Malte and Indelicato, Paul and Julien, Lucile and Kirch, Klaus and Knecht, Andreas and Liu, Yi-Wei and Machado, Jorge and Monteiro, Cristina M. B. and Mulhauser, Fran{\c c}oise and Naar, Boris and Nebel, Tobias and Nez, Fran{\c c}ois and dos Santos, Joaquim M. F. and Jos{\'e} Paulo Santos and Szabo, Csilla I and Taqqu, David and Veloso, Jo{\~a}o F. C. A. and Jan Vogelsang and Voss, Andreas and Weichelt, Birgit and Pohl, Randolf and Antognini, Aldo and Kottmann, Franz} } @article {Amaro_2021, title = {Stabilization method with the relativistic configuration-interaction calculation applied to two-electron resonances}, journal = {Physical Review A}, volume = {103}, number = {1}, year = {2021}, note = {n/a}, month = {jan}, publisher = {American Physical Society ({APS})}, abstract = {n/a}, doi = {10.1103/physreva.103.012811}, url = {https://doi.org/10.1103\%2Fphysreva.103.012811}, author = {P Amaro and J P Santos and Bhattacharyya, S and Mukherjee, T K and Saha, J. K.} } @book {6d0410dbbefe4eda8d73e05236c4b2ec, title = {Cultura Material, Cultura Cient{\'\i}fica: Patrim{\'o}nio Industrial para o Futuro}, year = {2021}, note = {

IH4Future (PTDC/FIS-aQM/30292/2017

}, month = {dec}, publisher = {Faculdade de Ci{\^e}ncias e Tecnologia, Universidade Nova de Lisboa}, organization = {Faculdade de Ci{\^e}ncias e Tecnologia, Universidade Nova de Lisboa}, address = {Portugal}, abstract = {

Material, Culture, Scientific Culture: Industrial Heritage for the Future

}, doi = {10.34619/e4vd-p551}, author = {Alison Wain and Diogo Castro and Rollo, {Maria Fernanda} and Frederico Nogueira and Gon{\c c}alo Santos and Filipe, {Maria da Gra{\c c}a} and Tissot, Isabel and Sampaio, {Jorge Miguel} and Santos, {Jos{\'e} Paulo} and Manuel Lemos and Marta Manso and Matthias Tissot and Guerra, Mauro and Miles Oglethorpe and Amaro, Pedro and Pedro Pedroso and Silva, Rui and Pessanha, Sofia and Silva, {Tiago A. N.}} } @article {J._P._Santos_87568685, title = {Fundamental Parameters Related to Selenium K\alpha and K\beta Emission X-ray Spectra}, journal = {Atoms}, year = {2021}, note = {n/a}, abstract = {n/a}, doi = {10.3390/atoms9010008}, url = {http://doi.org/10.3390/atoms9010008}, author = {J P Santos and Guerra, Mauro and Jorge M. Sampaio and Gon{\c c}alo R. V{\'\i}lia and C{\'e}sar A. Godinho and Daniel Pinheiro and Amaro, Pedro and Jos{\'e} P. Marques and Machado, Jorge and Indelicato, Paul and Parente, Fernando and Jos{\'e} Paulo Santos} } @article {Togawa_2020, title = {Observation of strong two-electron{\textendash}one-photon transitions in few-electron ions}, journal = {Physical Review A}, volume = {102}, number = {5}, year = {2020}, note = {n/a}, month = {nov}, publisher = {American Physical Society ({APS})}, abstract = {n/a}, doi = {10.1103/physreva.102.052831}, url = {https://doi.org/10.1103\%2Fphysreva.102.052831}, author = {M. Togawa and S. K{\~A}{\textonequarter}hn and C. Shah and P Amaro and R. Steinbr{\~A}{\textonequarter}gge and J. Stierhof and N. Hell and M. Rosner and K. Fujii and M. Bissinger and R. Ballhausen and M. Hoesch and J. Seltmann and S. Park and F. Grilo and F. S. Porter and J P Santos and M. Chung and T. St{\~A}{\textparagraph}hlker and J. Wilms and T. Pfeifer and G. V. Brown and M. A. Leutenegger and S. Bernitt and J. R. Crespo L{\'o}pez-Urrutia} } @article {J._P._Santos_75005553, title = {Reference-free measurements of the 1s2s2p2P1/2,3/2o\rightarrow1s22s2S1/2 and 1s2s2p4P5/2\rightarrow1s22s2S1/2 transition energies and widths in lithiumlike sulfur and argon ions}, journal = {Physical Review A}, year = {2020}, note = {n/a}, abstract = {n/a}, doi = {10.1103/PhysRevA.101.062505}, url = {http://doi.org/10.1103/PhysRevA.101.062505}, author = {J P Santos and Machado, J and Bian, Guojie and Nancy Paul and Trassinelli, M and P Amaro and M Guerra and Szabo, C. I. and Gumberidze, A. and Isac, J. M. and J P Santos and J. P. Desclaux and P. Indelicato} } @article {947bad94b0034a06b7c096fdb9409757, title = {Diagram, valence-to-core, and hypersatellite Kβ X-ray transitions in metallic chromium}, journal = {X-Ray Spectrometry}, volume = {48}, number = {5}, year = {2019}, note = {

info:eu-repo/grantAgreement/FCT/SFRH/SFRH\%2FBPD\%2F92455\%2F2013/PT$\#$ info:eu-repo/grantAgreement/FCT/5876/147413/PT$\#$ info:eu-repo/grantAgreement/FCT/5876/147256/PT$\#$ The financial support of the Swiss National Science Foundation (Grant No. 200020-146739) is acknowledged by F.?Z., J.?H., and J.-Cl.?D. M.?G. acknowledges the support of the FCT, under the Contract No. SFRH/BPD/92455/2013 and the project PTDC/FIS-AQM/31969/2017, ?Ultra-high-accuracy X-ray spectroscopy of transition metal oxides and rare earths.? This work was also partly supported by the research center grants nos. UID/FIS/04559/2013 to LIBPhys-UNL, and UID/MULTI/04046/2013 to BioISI, from the FCT/MCTES/PIDDAC.

}, pages = {351{\textendash}359}, publisher = {John Wiley \& Sons, Ltd.}, abstract = {

We report on measurements of the Kβ diagram, valence-to-core (VtC), and hypersatellite X-ray spectra induced in metallic Cr by photon single and double K-shell ionization. The experiment was carried out at the Stanford Synchrotron Radiation Lightsource using the seven-crystal Johann-type hard X-ray spectrometer of the beamline 6-2. For the Kβ diagram and VtC transitions, the present study confirms the line shape features observed in previous works, whereas the K h β hypersatellite transition was found to exhibit a complex spectral line shape and a characteristic low-energy shoulder. The energy shift of the hypersatellite relative to the parent diagram line was deduced from the measurements and compared with the result of extensive multiconfiguration Dirac{\textendash}Fock (MCDF) calculations. A very good agreement between experiment and theory was found. The MCDF calculations were also used to compute the theoretical line shape of the hypersatellite. A satisfactory agreement was obtained between the overall shapes of the experimental and theoretical spectra, but deviations were observed on the low- and high-energy flanks of the hypersatellite line. The discrepancies were explained by chemical effects, which were not considered in the MCDF calculations performed for isolated atoms.

}, issn = {0049-8246}, doi = {10.1002/xrs.3019}, author = {Faisal Zeeshan and Joanna Hoszowska and Dousse, {Jean Claude} and Dimosthenis Sokaras and Weng, {Tsu Chien} and Roberto Alonso-Mori and Matjaz Kav{\v c}i{\v c} and Guerra, Mauro and Sampaio, {Jorge Miguel} and Parente, Fernando and Indelicato, Paul and Marques, {Jos{\'e} Pires} and Santos, {Jos{\'e} Paulo}} } @article {J._P._Santos_60599727, title = {Revisiting the Fe xvii Line Emission Problem: Laboratory Measurements of the 3s{\textendash}2p and 3d{\textendash}2p Line-formation Channels}, journal = {The Astrophysical Journal}, year = {2019}, note = {n/a}, abstract = {n/a}, doi = {10.3847/1538-4357/ab2896}, url = {http://doi.org/10.3847/1538-4357/ab2896}, author = {J P Santos and Chintan Shah and Jos{\'e} R. Crespo L{\'o}pez-Urrutia and Ming Feng Gu and Thomas Pfeifer and Jos{\'e} Marques and Filipe Grilo and Jos{\'e} Paulo Santos and Amaro, Pedro} } @article {LIDON:2018gg, title = {{SELENIUM BIOFORTIFICATION OF RICE THROUGH FOLIAR APPLICATION WITH SELENITE AND SELENATE}}, journal = {Experimental Agriculture}, year = {2018}, note = {

n/a

}, month = {apr}, pages = {1{\textendash}15}, abstract = {

n/a

}, author = {LIDON, FERNANDO CEBOLA and OLIVEIRA, KARLIANA and GALHANO, CARLOS and Guerra, Mauro and RIBEIRO, MARIA MANUELA and PELICA, JO{\~A}O and PATACO, IN{\^E}S and RAMALHO, JOS{\'E} COCHICHO and LEIT{\~A}O, ANT{\'O}NIO EDUARDO and ALMEIDA, ANA SOFIA and CAMPOS, PAULA SCOTTI and Ribeiro-Barros, Ana and PAIS, ISABEL P and Silva, Maria Manuela and Carvalho, Maria Luisa and Santos, Jose Paulo and PESSOA, MARIA FERNANDA and REBOREDO, FERNANDO HENRIQUE} } @article {Machado:2018ge, title = {{High-precision measurements of $n=2\rightarrow n=1$ transition energies and level widths in He- and Be-like argon ions}}, journal = {Phys. Rev.}, volume = {97}, number = {3}, year = {2018}, note = {n/a}, pages = {032517}, abstract = {n/a}, author = {Machado, J and Szabo, C. I. and J P Santos and P Amaro and M Guerra and Gumberidze, A. and Bian, Guojie and Isac, J. M. and P. Indelicato} } @article {Monteiro:2018hba, title = {{On the double peak structure of avalanche photodiode response to monoenergetic x-rays at various temperatures and bias voltages}}, journal = {J. Inst.}, volume = {13}, number = {01}, year = {2018}, note = {n/a}, pages = {C01033{\textendash}C01033}, abstract = {n/a}, author = {Monteiro, C M B and Amaro, F D and Sousa, M S and Abdou-Ahmed, M and P Amaro and Biraben, F. and Chen, T. and Covita, D S and Dax, A J and Diepold, M and Fernandes, L M P and Franke, B and Galtier, S and Gouv{\^e}a, A L and G{\"o}tzfried, J and Graf, T and Hansch, T W and Hildebrandt, M and P. Indelicato and Julien, L. and Kirch, K and Knecht, A and Kottmann, F and Krauth, J J and Liu, Y. and Machado, J and Mulhauser, F and Naar, B and Nebel, T and Nez, F. and Pohl, R and J P Santos and Santos, J M F dos and Schuhmann, K and Szabo, C. I. and Taqqu, D and Veloso, J F C A and Antognini, A} } @article {Amaro:2018cp, title = {{Quantum interference in laser spectroscopy of highly charged lithiumlike ions}}, journal = {Phys. Rev. A}, volume = {97}, year = {2018}, note = {n/a}, pages = {022510}, abstract = {n/a}, author = {Amaro, Pedro and Loureiro, Ulisses and Safari, Laleh and Fratini, Filippo and Indelicato, Paul and Stohlker, Thomas and Santos, Jose Paulo} } @article {Fratini:2018em, title = {{Two-photon processes based on quantum commutators}}, year = {2018}, note = {n/a}, pages = {1{\textendash}13}, abstract = {n/a}, author = {F. Fratini and Safari, L and P Amaro and J P Santos} } @conference {12488, title = {Laser Spectroscopy of Muonic Atoms and Ions}, booktitle = {Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)}, year = {2017}, note = {n/a}, month = {Nov 24}, pages = {1-12}, publisher = {Journal of the Physical Society of Japan}, organization = {Journal of the Physical Society of Japan}, abstract = {n/a}, isbn = {4-89027-125-2}, url = {http://journals.jps.jp/doi/10.7566/JPSCP.18.011021}, author = {Pohl, Randolf and Nez, Fran{\c c}ois and Fernandes, Luis M. P. and Ahmed, Marwan Abdou and Amaro, Fernando D. and Amaro, Pedro and Biraben, Fran{\c c}ois and Cardoso, Jo{\~a}o M. R. and Covita, Daniel S. and Dax, Andreas and Dhawan, Satish and Diepold, Marc and Franke, Beatrice and Galtier, Sandrine and Giesen, Adolf and Gouvea, Andrea L and G{\"o}tzfried, Johannes and Graf, Thomas and H{\"a}nsch, Theodor W. and Hildebrandt, Malte and Indelicato, Paul and Julien, Lucile and Kirch, Klaus and Knecht, Andreas and Knowles, Paul and Kottmann, Franz and Krauth, Julian J and Le Bigot, Eric-Olivier and Liu, Yi-Wei and Lopes, Jos{\'e} A. M. and Ludhova, Livia and Machado, Jorge and Monteiro, Cristina M. B. and Mulhauser, Fran{\c c}oise and Nebel, Tobias and Rabinowitz, Paul and dos Santos, Joaquim M. F. and Santos, Jose Paulo and Schaller, Lukas A. and Schuhmann, Karsten and Schwob, Catherine and Szabo, Csilla I and Taqqu, David and Veloso, Jo{\~a}o F. C. A. and Voss, Andreas and Weichelt, Birgit and Antognini, Aldo} } @article {12494, title = {The investigation of K-shell fluorescence parameters of Zn-Fe alloys with different grain size and microstrain values}, journal = {X-Ray Spectrometry}, volume = {406}, year = {2017}, note = {n/a}, month = {Mar 14}, pages = {1481-10}, abstract = {

It is known that zinc alloys with iron group metals have better corrosion resistance than pure zinc. Owing to the corrosion resistance of these alloys, Zn{\textendash}Fe coatings are widely used in automotive industry...

}, url = {http://doi.wiley.com/10.1002/xrs.2763}, author = {Kup Aylikci, N and Sampaio, J M and Kahoul, A and Aylikci, V and Karahan, {\.I} H and M Guerra and J P Santos and J. P. Marques and Tirasoglu, E.} } @article {12495, title = {Determination of Nickel and Manganese Contaminants in Pharmaceutical Iron Supplements Using Energy Dispersive X-ray Fluorescence}, journal = {Applied Spectroscopy}, volume = {71}, number = {3}, year = {2017}, note = {n/a}, month = {Mar 13}, pages = {432-437}, abstract = {n/a}, url = {http://journals.sagepub.com/doi/10.1177/0003702816670912}, author = {Cardoso, Pedro and Amaro, Pedro and Santos, Jose Paulo and de Assis, Joaquim T and Carvalho, Maria Luisa} } @article {12491, title = {Relativistic calculations of screening parameters and atomic radii of neutral atoms}, journal = {Atomic Data and Nuclear Data Tables}, volume = {117-118}, year = {2017}, note = {n/a}, month = {Jul 14}, pages = {439-457}, publisher = {Elsevier Inc.}, abstract = {

Atomic Data and Nuclear Data Tables, 117-118 (2017) 439-457. doi:10.1016/j.adt.2017.01.001

}, url = {http://dx.doi.org/10.1016/j.adt.2017.01.001}, author = {M Guerra and P Amaro and J P Santos and P. Indelicato} } @article {12497, title = {Detection limits evaluation of a portable energy dispersive X-ray fluorescence setup using different filter combinations}, journal = {X-Ray Spectrometry}, volume = {46}, number = {2}, year = {2017}, note = {n/a}, month = {Jan 03}, pages = {102-106}, abstract = {

In this paper, we study the performance of a portable energy dispersive X-ray fluorescence spectrometer by making use of different filter configurations at the X-ray tube output. To fulfill this purpose,...

}, url = {http://doi.wiley.com/10.1002/xrs.2737}, author = {Pessanha, Sofia and Samouco, Ana and Ad{\~a}o, Ricardo and Carvalho, Maria Luisa and Santos, Jose Paulo and Amaro, Pedro}, editor = {Boman, Johan} } @article {12496, title = {Elemental mapping in a contemporary miniature by full-field X-ray fluorescence imaging with gaseous detector vs. scanning X-ray fluorescence imaging with polycapillary optics}, year = {2017}, note = {n/a}, month = {Feb 03}, pages = {1-7}, publisher = {Elsevier B.V.}, abstract = {

Spectrochimica Acta Part B: Atomic Spectroscopy, 129 (2016) 1-7. doi:10.1016/j.sab.2016.12.006

}, author = {Silva, A L M and Cirino, S and M. L. Carvalho and Manso, M. and Pessanha, S. and Azevedo, C D R and Carramate, L F N D and J P Santos and M Guerra and Veloso, J F C A} } @article {12492, title = {Validation of the Geant4 Monte Carlo package for X-ray fluorescence spectroscopy in triaxial geometry}, journal = {Spectrochimica Acta Part B: Atomic Spectroscopy}, volume = {130}, number = {C}, year = {2017}, note = {n/a}, month = {Apr 01}, pages = {60-66}, publisher = {Elsevier B.V.}, abstract = {

Spectrochimica Acta Part B: Atomic Spectroscopy, 130 (2017) 60-66. doi:10.1016/j.sab.2017.02.012

}, url = {http://dx.doi.org/10.1016/j.sab.2017.02.012}, author = {Amaro, Pedro and Santos, Jose Paulo and Samouco, Ana and Ad{\~a}o, Ricardo and Martins, Lu{\'\i}s Souto and Weber, Sebastian and Tashenov, Stanislav and Carvalho, Maria Luisa and Pessanha, Sofia} } @article {12498, title = {A novel portable energy dispersive X-ray fluorescence spectrometer with triaxial geometry}, journal = {J. Inst.}, volume = {12}, number = {01}, year = {2017}, note = {n/a}, pages = {P01014}, abstract = {n/a}, author = {Pessanha, S. and Alves, M. and Sampaio, J M and J P Santos and M. L. Carvalho and M Guerra} } @article {10145, title = {Determination of Nickel and Manganese Contaminants in Pharmaceutical Iron Supplements using Energy Dispersive X-ray Fluorescence.}, journal = {Applied Spectroscopy}, year = {2016}, note = {n/a}, month = {Sep 30}, abstract = {

In this study, we investigate the capability of energy dispersive X-ray fluorescence (EDXF) spectrometry in a triaxial geometry apparatus as a fast and nondestructive determination method of both dominant and contaminant elements in pharmaceutical iron supplements. The following iron supplements brands with their respective active ingredients were analyzed: Neutrofer f{\'o}lico (iron gylcinate), Anemifer (iron(II) sulfate monohydrate), Noripurum (iron(III)-hydroxide polymaltose complex), Sulferbel (iron(II) sulfate monohydrate), and Combiron F{\'o}lico (carbonyl iron). Although we observe a good agreement between the iron content obtained by the present method and that indicated in the supplement\'s prescribed dose, we observe contamination by manganese and nickel of up to 180 μg and 36 μg, respectively. These contents correspond to 7.2\% and 14.4\% of the permitted daily exposure of manganese and nickel, respectively, for an average adult individual as determined by the European Medicine Agency (EMEA). The method was successfully validated against the concentrations of several certified reference materials of biological light matrices with similar concentrations of contaminants. Moreover, we also validated our method by comparing the concentrations with those obtained with the inductively coupled plasma-atomic emission technique.

}, url = {http://asp.sagepub.com/content/early/2016/09/30/0003702816670912.abstract}, author = {Cardoso, Pedro and Amaro, Pedro and Santos, Jose Paulo and de Assis, Joaquim T and Carvalho, Maria Luisa} } @article {10151, title = {Relativistic evaluation of the two-photon decay of the metastable 1s22s2p 3P0 state in berylliumlike ions with an effective-potential model}, journal = {Physical Review A}, volume = {93}, number = {3}, year = {2016}, note = {n/a}, month = {Mar 07}, pages = {032502-8}, publisher = {American Physical Society}, abstract = {

The two-photon $1{s}^{2}2s2p\phantom{\rule{0.16em}{0ex}}{}^{3}{P}_{0}\ensuremath{\rightarrow}1{s}^{2}{s}^{2}\phantom{\rule{0.16em}{0ex}}{}^{1}{S}_{0}$ transition in berylliumlike ions is investigated theoretically within a fully relativistic framework and a second-order perturbation theory. We focus our analysis on how electron correlation, as well as the negative-energy spectrum, can affect the forbidden $E1M1$ decay rate. For this purpose, we include the electronic correlation via an effective local potential and within a single-configuration-state model. Due to its experimental interest, evaluations of decay rates are performed for berylliumlike xenon and uranium. We find that the negative-energy contribution can be neglected at the present level of accuracy in the evaluation of the decay rate. On the other hand, if contributions of electronic correlation are not carefully taken into account, it may change the lifetime of the metastable state by up to 20\%. By performing a fully relativistic $jj$-coupling calculation, we find a decrease of the decay rate by two orders of magnitude compared to nonrelativistic $LS$-coupling calculations, for the selected heavy ions.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.93.032502}, author = {Amaro, Pedro and Fratini, Filippo and Safari, Laleh and Machado, Jorge and Guerra, Mauro and Indelicato, Paul and Santos, Jose Paulo} } @article {8057, title = {Electron impact ionization cross-sections for few-electron uranium ions}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {48}, number = {14}, year = {2015}, note = {n/a}, month = {May 21}, pages = {1-5}, publisher = {IOP Publishing}, abstract = {

Journal of Physics B: Atomic, Molecular and Optical Physics, 48(2015) 144027. doi:10.1088/0953-4075/48/14/144027

}, url = {http://dx.doi.org/10.1088/0953-4075/48/14/144027}, author = {M Guerra and Th St{\"o}hlker and P Amaro and Machado, J and J P Santos} } @article {8102, title = {Analytical evaluation of atomic form factors: Application to Rayleigh scattering}, journal = {Journal of Mathematical Physics}, volume = {56}, number = {5}, year = {2015}, note = {n/a}, month = {May}, pages = {052105-9}, abstract = {n/a}, url = {http://scitation.aip.org/content/aip/journal/jmp/56/5/10.1063/1.4921227}, author = {Safari, L and J P Santos and P Amaro and Jankala, K and F. Fratini} } @article {8061, title = {Improved x-ray detection and particle identification with avalanche photodiodes}, journal = {Review of Scientific Instruments}, volume = {86}, number = {5}, year = {2015}, note = {n/a}, month = {May}, pages = {053102-7}, abstract = {n/a}, url = {http://scitation.aip.org/content/aip/journal/rsi/86/5/10.1063/1.4921195}, author = {Diepold, Marc and Fernandes, Luis M. P. and Machado, Jorge and Amaro, Pedro and Abdou-Ahmed, Marwan and Amaro, Fernando D. and Antognini, Aldo and Biraben, Fran{\c c}ois and Chen, Tzu-Ling and Covita, Daniel S. and Dax, Andreas J and Franke, Beatrice and Galtier, Sandrine and Gouvea, Andrea L and G{\"o}tzfried, Johannes and Graf, Thomas and H{\"a}nsch, Theodor W. and Hildebrandt, Malte and Indelicato, Paul and Julien, Lucile and Kirch, Klaus and Knecht, Andreas and Kottmann, Franz and Krauth, Julian J and Liu, Yi-Wei and Monteiro, Cristina M. B. and Mulhauser, Fran{\c c}oise and Naar, Boris and Nebel, Tobias and Nez, Fran{\c c}ois and Santos, Jose Paulo and dos Santos, Joaquim M. F. and Schuhmann, Karsten and Szabo, Csilla I and Taqqu, David and Veloso, Jo{\~a}o F. C. A. and Voss, Andreas and Weichelt, Birgit and Pohl, Randolf} } @article {8090, title = {Double KK excited states in highly charged sulphur}, journal = {Journal of Physics: Conference Series}, volume = {635}, year = {2015}, note = {

n/a

}, month = {Jun}, pages = {022071}, abstract = {

n/a

}, author = {P Amaro and J. P. Marques and P. Indelicato and Mukherjee, T K and Saha, J. K. and Tribedi, L C and J P Santos} } @article {8120, title = {Quantum interference shifts in laser spectroscopy with elliptical polarization}, journal = {Physical Review A}, volume = {92}, number = {6}, year = {2015}, note = {n/a}, month = {Dec 31}, pages = {062506-5}, abstract = {n/a}, url = {http://link.aps.org/doi/10.1103/PhysRevA.92.062506}, author = {Amaro, Pedro and Fratini, Filippo and Safari, Laleh and Antognini, Aldo and Indelicato, Paul and Pohl, Randolf and Santos, Jose Paulo} } @article {8117, title = {Quantum interference effects in laser spectroscopy of muonic hydrogen, deuterium, and helium-3}, journal = {Physical Review A}, volume = {92}, number = {2}, year = {2015}, note = {n/a}, month = {Aug 28}, pages = {022514-7}, abstract = {n/a}, url = {http://link.aps.org/doi/10.1103/PhysRevA.92.022514}, author = {Amaro, Pedro and Franke, Beatrice and Krauth, Julian J and Diepold, Marc and Fratini, Filippo and Safari, Laleh and Machado, Jorge and Antognini, Aldo and Kottmann, Franz and Indelicato, Paul and Pohl, Randolf and Santos, Jose Paulo} } @article {8154, title = {Single differential electron impact ionization cross sections in the binary-encounter- Bethe approximation for the low binding energy regime}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {48}, number = {18}, year = {2015}, note = {n/a}, month = {Aug 03}, pages = {1-9}, publisher = {IOP Publishing}, abstract = {

Journal of Physics B: Atomic, Molecular and Optical Physics, 48(2015) 185202. doi:10.1088/0953-4075/48/18/185202

}, url = {http://dx.doi.org/10.1088/0953-4075/48/18/185202}, author = {M Guerra and P Amaro and Machado, J and J P Santos} } @article {8051, title = {Spatially resolved determination of toxic trace elements in plants of Panasqueira mining region using micro X-ray fluorescence}, journal = {Microscopy and Microanalysis}, volume = {21}, year = {2015}, note = {n/a}, month = {Aug}, pages = {54-55}, abstract = {n/a}, url = {http://journals.cambridge.org/article_S1431927614013944}, author = {M Guerra and P{\'e}-Leve Santos, S C and Barroso, A. M. E. and Fonseca, C. P. S. and Eloy Cruz, M and P Amaro and Figueirinhas, J. L. and M. L. Carvalho and J P Santos} } @article {8064, title = {Modified Binary-Encounter-Bethe Model for Electron Impact Ionization Cross Sections of Highly Charged Ions }, journal = {Journal of Physics: Conference Series}, volume = {635}, year = {2015}, note = {n/a}, pages = {052067}, abstract = {n/a}, url = {X}, author = {M Guerra and P Amaro and Machado, J and J P Santos} } @article {8095, title = {A vacuum double-crystal spectrometer for reference-free X-ray spectroscopy of highly charged ions}, journal = {Radiation Physics and Chemistry}, volume = {98}, number = {C}, year = {2014}, note = {n/a}, month = {May 01}, pages = {132-149}, publisher = {Elsevier}, abstract = {

Radiation Physics and Chemistry, 98 + (2014) 132-149. doi:10.1016/j.radphyschem.2014.01.015

}, url = {http://dx.doi.org/10.1016/j.radphyschem.2014.01.015}, author = {P Amaro and Szabo, C. I. and S. Schlesser and Gumberidze, A. and Kessler, E. G. and Henins, A. and Le Bigot, E. O. and Trassinelli, M and Isac, J. M. and Travers, P and M Guerra and J P Santos and P. Indelicato} } @article {6852, title = {A vacuum double-crystal spectrometer for reference-free X-ray spectroscopy of highly charged ions}, journal = {Radiation Physics and Chemistry}, volume = {98}, number = {C}, year = {2014}, note = {n/a}, month = {Jun 01}, pages = {132-149}, publisher = {Elsevier}, abstract = {

Radiation Physics and Chemistry, 98 + (2014) 132-149. doi:10.1016/j.radphyschem.2014.01.015

}, url = {http://dx.doi.org/10.1016/j.radphyschem.2014.01.015}, author = {P Amaro and Szabo, C. I. and S. Schlesser and Gumberidze, A. and Kessler, E. G. and Henins, A. and Le Bigot, E. O. and Trassinelli, M and Isac, J. M. and Travers, P and M Guerra and J P Santos and P. Indelicato} } @article {6849, title = {Angular and polarization analysis for two-photon decay of \<span class=\"aps-inline-formula\"\>\<math xmlns=\"http://www.w3.org/1998/Math/MathML\"\>\<mrow\>\<mn\>2\</mn\>\<mi\>s\</mi\>\</mrow\>\</math\>\&}, journal = {Physical Review A}, volume = {90}, number = {1}, year = {2014}, note = {n/a}, month = {Jul 29}, pages = {014502}, abstract = {

The amplitude of two-photon transitions between hyperfine states in hydrogenlike ions is derived based on the relativistic Dirac equation and second-order perturbation theory. We study angular and linear polarization properties of the photon pair emitted in the decay of $2s$ states, where spin-flip and non-spin-flip transitions are highlighted. We pay particular attention to hydrogenlike uranium, since it is an ideal candidate for investigating relativistic and high-multipole effects, such as spin-flip transitions. Two types of emission patterns are identified: (i) non-spin-flip transitions are found to be characterized by an angular distribution of the type $W($\theta${})$\sim${}1+{cos}^{2}$\theta${}$ while the polarizations of the emitted photons are parallel; and (ii) spin-flip transitions have somewhat smaller decay rates and are found to be characterized by an angular distribution of the type $W($\theta${})$\sim${}1$-${}1/3{cos}^{2}$\theta${}$ while the polarizations of the emitted photons are orthogonal, where $$\theta${}$ is the angle between photons directions. Deviations due to nondipole and relativistic contributions are evaluated for both types of transitions. This work is the first step toward exploring the effect of the nucleus over the angular and polarization properties of the photon pairs emitted by two-photon transitions.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.90.014502}, author = {Safari, L and P Amaro and J P Santos and F. Fratini} } @article {8063, title = {Angular and polarization analysis for two-photon decay of \<span class=\"aps-inline-formula\"\>\<math xmlns=\"http://www.w3.org/1998/Math/MathML\"\>\<mrow\>\<mn\>2\</mn\>\<mi\>s\</mi\>\</mrow\>\</math\>\&}, journal = {Physical Review A}, volume = {90}, number = {1}, year = {2014}, note = {n/a}, month = {Jul 29}, pages = {014502}, abstract = {

The amplitude of two-photon transitions between hyperfine states in hydrogenlike ions is derived based on the relativistic Dirac equation and second-order perturbation theory. We study angular and linear polarization properties of the photon pair emitted in the decay of $2s$ states, where spin-flip and non-spin-flip transitions are highlighted. We pay particular attention to hydrogenlike uranium, since it is an ideal candidate for investigating relativistic and high-multipole effects, such as spin-flip transitions. Two types of emission patterns are identified: (i) non-spin-flip transitions are found to be characterized by an angular distribution of the type $W($\theta${})$\sim${}1+{cos}^{2}$\theta${}$ while the polarizations of the emitted photons are parallel; and (ii) spin-flip transitions have somewhat smaller decay rates and are found to be characterized by an angular distribution of the type $W($\theta${})$\sim${}1$-${}1/3{cos}^{2}$\theta${}$ while the polarizations of the emitted photons are orthogonal, where $$\theta${}$ is the angle between photons directions. Deviations due to nondipole and relativistic contributions are evaluated for both types of transitions. This work is the first step toward exploring the effect of the nucleus over the angular and polarization properties of the photon pairs emitted by two-photon transitions.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.90.014502}, author = {Safari, L and P Amaro and J P Santos and F. Fratini} } @article {6850, title = {Quantized form factor shift in the presence of free electron laser radiation}, journal = {EPL (Europhysics Letters)}, volume = {107}, number = {1}, year = {2014}, note = {n/a}, month = {Jul 01}, pages = {13002}, publisher = {IOP Publishing}, abstract = {

In electron scattering, the target form factors contribute significantly to the diffraction pattern and carry information on the target electromagnetic charge distribution. Here we show that the presence of electromagnetic radiation, as intense as currently available in free electron lasers, shifts the dependence of the target form factors by a quantity that depends on the number of photons absorbed or emitted by the electron as well as on the parameters of the electromagnetic radiation. As example, we show the impact of intense ultraviolet and soft X-ray radiation on elastic electron scattering by the Ne-like argon ion and by the xenon atom. We find that the shift brought by the radiation to the form factor is of the order of some percent. Our results may open up a new avenue to explore matter with the assistance of laser.

}, url = {http://iopscience.iop.org/0295-5075/107/1/13002/article/}, author = {F. Fratini and Safari, L and Hayrapetyan, A G and Jankala, K and P Amaro and J P Santos} } @article {8145, title = {Quantized form factor shift in the presence of free electron laser radiation}, journal = {EPL (Europhysics Letters)}, volume = {107}, number = {1}, year = {2014}, note = {n/a}, month = {Jul 01}, pages = {13002}, publisher = {IOP Publishing}, abstract = {

In electron scattering, the target form factors contribute significantly to the diffraction pattern and carry information on the target electromagnetic charge distribution. Here we show that the presence of electromagnetic radiation, as intense as currently available in free electron lasers, shifts the dependence of the target form factors by a quantity that depends on the number of photons absorbed or emitted by the electron as well as on the parameters of the electromagnetic radiation. As example, we show the impact of intense ultraviolet and soft X-ray radiation on elastic electron scattering by the Ne-like argon ion and by the xenon atom. We find that the shift brought by the radiation to the form factor is of the order of some percent. Our results may open up a new avenue to explore matter with the assistance of laser.

}, url = {http://iopscience.iop.org/0295-5075/107/1/13002/article/}, author = {F. Fratini and Safari, L and Hayrapetyan, A G and Jankala, K and P Amaro and J P Santos} } @article {8111, title = {High-resolution x-ray spectra from highly charged Si, S and Cl ions showing evidence of fluorescence active resonant states}, journal = {Journal of Physics: Conference Series}, volume = {488}, number = {13}, year = {2014}, note = {n/a}, month = {Apr 10}, pages = {132027-2}, publisher = {IOP Publishing}, abstract = {

We have measured the x-ray spectra from highly charged Si, S and Cl ions in collisions with thin foils using a high-resolution x-ray spectrometer. The observed lines have been assigned to various transitions in H-, He- and Li-like ions. For proper identification of line positions, the theoretical calculations have been carried out using a state-of-the-art MCDF code including QED effects, with which the experimental data is in excellent agreement. We have also observed, for the first time, x-rays arising out of the decay of long-lived resonant states in the He-like ions of each species. Details will be presented.

}, url = {http://stacks.iop.org/1742-6596/488/i=13/a=132027?key=crossref.ca3a558053867d6b82a4342f9946cefd}, author = {Kasthurirangan, S and Saha, J. K. and Agnihotri, A. N. and Banerjee, A and Kumar, A and Misra, D and J P Santos and A. M. Costa and P. Indelicato and Mukherjee, T K and Tribedi, L C} } @article {5676, title = {Absolute measurements and simulations of x-ray line energies of highly charged ions with a double-crystal spectrometer}, volume = {T156}, year = {2013}, note = {n/a}, month = {Sep 23}, pages = {014104}, abstract = {n/a}, url = {http://stacks.iop.org/1402-4896/2013/i=T156/a=014104?key=crossref.fbaa38a1c4861ecbc3a487c810be06f2}, author = {P Amaro and S. Schlesser and M Guerra and Le Bigot, E and J P Santos and Szabo, C. I. and Gumberidze, A. and P. Indelicato} } @article {8052, title = {Absolute measurements and simulations of x-ray line energies of highly charged ions with a double-crystal spectrometer}, journal = {Physica Scripta}, volume = {T156}, year = {2013}, note = {n/a}, month = {Sep 23}, pages = {014104}, abstract = {n/a}, url = {http://stacks.iop.org/1402-4896/2013/i=T156/a=014104?key=crossref.fbaa38a1c4861ecbc3a487c810be06f2}, author = {P Amaro and S. Schlesser and M Guerra and Le Bigot, E and J P Santos and Szabo, C. I. and Gumberidze, A. and P. Indelicato} } @article {6862, title = {Ion temperature and x-ray line width measurements of highly charged argon ions in an ECR ion source}, journal = {Physica Scripta}, volume = {T156}, year = {2013}, note = {n/a}, month = {Sep 23}, pages = {014077}, abstract = {n/a}, url = {http://stacks.iop.org/1402-4896/2013/i=T156/a=014077?key=crossref.f2da41f889b9520c88b7506c96702da1}, author = {Szabo, C. I. and P Amaro and M Guerra and J P Santos and Gumberidze, A. and Attard, J and P. Indelicato} } @article {8156, title = {Ion temperature and x-ray line width measurements of highly charged argon ions in an ECR ion source}, journal = {Physica Scripta}, volume = {T156}, year = {2013}, note = {n/a}, month = {Sep 23}, pages = {014077}, abstract = {n/a}, url = {http://stacks.iop.org/1402-4896/2013/i=T156/a=014077?key=crossref.f2da41f889b9520c88b7506c96702da1}, author = {Szabo, C. I. and P Amaro and M Guerra and J P Santos and Gumberidze, A. and Attard, J and P. Indelicato} } @article {8134, title = {Analysis of the charge state distribution in an ECRIS Ar plasma using high-resolution x-ray spectra}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {46}, number = {6}, year = {2013}, note = {n/a}, month = {Mar 01}, pages = {065701}, publisher = {IOP Publishing}, abstract = {

In this work, we obtained a charge state distribution inside an Ar plasma produced by an electron{\textendash}cyclotron-resonance ion source. The processes that lead to the observed lines in x-ray spectra are identified and included in the simulated x-ray spectrum. The geometrical constraints of the flat double crystal spectrometer, used to measure the x-ray spectrum, are investigated as they are crucial for correctly obtaining the ion densities from the observed transition amplitudes. Multiple electron impact ionization is included, and a realistic electron velocity distribution is taken into account. The charge state distribution of the Ar ions is compared to measured extracted ionic currents.

}, url = {http://iopscience.iop.org/0953-4075/46/6/065701/}, author = {M Guerra and P Amaro and Szabo, C. I. and Gumberidze, A. and P. Indelicato and J P Santos} } @article {6865, title = {Analysis of the charge state distribution in an ECRIS Ar plasma using high-resolution x-ray spectra}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {46}, number = {6}, year = {2013}, note = {n/a}, month = {Apr 01}, pages = {065701}, publisher = {IOP Publishing}, abstract = {

In this work, we obtained a charge state distribution inside an Ar plasma produced by an electron{\textendash}cyclotron-resonance ion source. The processes that lead to the observed lines in x-ray spectra are identified and included in the simulated x-ray spectrum. The geometrical constraints of the flat double crystal spectrometer, used to measure the x-ray spectrum, are investigated as they are crucial for correctly obtaining the ion densities from the observed transition amplitudes. Multiple electron impact ionization is included, and a realistic electron velocity distribution is taken into account. The charge state distribution of the Ar ions is compared to measured extracted ionic currents.

}, url = {http://iopscience.iop.org/0953-4075/46/6/065701/}, author = {M Guerra and P Amaro and Szabo, C. I. and Gumberidze, A. and P. Indelicato and J P Santos} } @article {6867, title = {Observation of 2p3 d (1Po){\textrightarrow} 1s3d (1De) Radiative Transition in He-like Si, S, and Cl Ions}, journal = {Physical Review Letters}, volume = {111}, year = {2013}, note = {n/a}, pages = {243201}, abstract = {n/a}, url = {http://prl.aps.org/abstract/PRL/v111/i24/e243201}, author = {Kasthurirangan, S and Saha, J. K. and Agnihotri, A. N. and Bhattacharyya, S and Misra, D and Kumar, A and Mukherjee, P K and J P Santos and A. M. Costa and P. Indelicato and Mukherjee, T K and Tribedi, L C} } @article {8104, title = {Observation of 2p3 d (1Po){\textrightarrow} 1s3d (1De) Radiative Transition in He-like Si, S, and Cl Ions}, journal = {Physical Review Letters}, volume = {111}, year = {2013}, note = {n/a}, pages = {243201}, abstract = {n/a}, url = {http://prl.aps.org/abstract/PRL/v111/i24/e243201}, author = {Kasthurirangan, S and Saha, J. K. and Agnihotri, A. N. and Bhattacharyya, S and Misra, D and Kumar, A and Mukherjee, P K and J P Santos and A. M. Costa and P. Indelicato and Mukherjee, T K and Tribedi, L C} } @article {5671, title = {Reference free, high-precision measurements of transition energies in few electron argon ions}, journal = {AIP APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY: Twenty-Second International Conference}, volume = {1525}, number = {1}, year = {2013}, note = {

journal = {AIP Conference Proceedings}

}, pages = {68-72}, publisher = {AIP}, abstract = {

The use of a vacuum double crystal spectrometer, coupled to an electron-cyclotron resonance ion source (ECRIS), allows to measure low-energy x-ray transitions energies in highly-charged ions with accuracies of the order of a few parts per million. We have used this installation to measure the 1s2p 1 P1 - 1s2 1 S0 diagram line and the 1s2s 3 S1 - 1s2 1 S0 forbidden M1 transition energies in helium-like argon, the 1s2s2p 2 P j 1s2 2s 2 S1/2 transitions in lithium-like argon and the 1s2s2 2p 1 P1 - 1s2 2s2 1 S0 transition in beryllium-like argon. These transition measurements have accuracies between 2 and 4 ppm depending on the line intensity. Thanks to the excellent agreement between the simulations and the measurements, we were also able to measure the transition width of all the allowed transitions. The results are compared to recent QED and relativistic many-body calculations.

}, url = {http://link.aip.org/link/?APC/1525/68/1}, author = {Szabo, Csilla I and Amaro, Pedro and Guerra, Mauro and Schlesser, Sophie and Gumberidze, Alexander and Santos, Jose Paulo and Indelicato, Paul}, editor = {McDaniel, Floyd D and Doyle, Barney L and Glass, Gary A and Wang, Yongqiang} } @article {8076, title = {Reference free, high-precision measurements of transition energies in few electron argon ions}, journal = {AIP Conf. Proc.}, volume = {1525}, number = {1}, year = {2013}, note = {

journal = {AIP Conference Proceedings}

}, pages = {68-72}, publisher = {AIP}, abstract = {

The use of a vacuum double crystal spectrometer, coupled to an electron-cyclotron resonance ion source (ECRIS), allows to measure low-energy x-ray transitions energies in highly-charged ions with accuracies of the order of a few parts per million. We have used this installation to measure the 1s2p 1 P1 - 1s2 1 S0 diagram line and the 1s2s 3 S1 - 1s2 1 S0 forbidden M1 transition energies in helium-like argon, the 1s2s2p 2 P j 1s2 2s 2 S1/2 transitions in lithium-like argon and the 1s2s2 2p 1 P1 - 1s2 2s2 1 S0 transition in beryllium-like argon. These transition measurements have accuracies between 2 and 4 ppm depending on the line intensity. Thanks to the excellent agreement between the simulations and the measurements, we were also able to measure the transition width of all the allowed transitions. The results are compared to recent QED and relativistic many-body calculations.

}, url = {http://link.aip.org/link/?APC/1525/68/1}, author = {Szabo, Csilla I and Amaro, Pedro and Guerra, Mauro and Schlesser, Sophie and Gumberidze, Alexander and Santos, Jose Paulo and Indelicato, Paul}, editor = {McDaniel, Floyd D and Doyle, Barney L and Glass, Gary A and Wang, Yongqiang} } @unpublished {8140, title = {A vacuum double-crystal spectrometer for reference-free highly charged ions X-ray spectroscopy}, year = {2012}, note = {n/a}, month = {Oct 23}, pages = {1-22}, edition = {Submitted to Radiation Physics and Chemistry, Radiat. Phys. Chem.}, abstract = {n/a}, author = {P Amaro and Szabo, Csilla I} } @article {2897, title = {Lead in liver and kidney of exposed rats: Aging accumulation study.}, journal = {J. Trace Elem. Med Biol.}, volume = {26}, year = {2012}, note = {

n/a

}, month = {Oct}, pages = {285}, abstract = {

The concentration of lead in liver and kidneys of Wistar rats, fed with lead since fetal period in relation to their age and to a control group, was determined. A group of rats was exposed to lead acetate (n=30) in drinking water and the other group was exposed to normal water (n=20). Samples were collected from rats aging between 1 and 11 months and were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) without any chemical preparation. The EDXRF results were assessed by the PIXE (Proton Induced X-ray Emission) technique. The formaldehyde used to preserve the samples was also analyzed by ETAAS (Electro-Thermal Atomic Absorption Spectrometry) in order to verify if there was any loss of lead from the samples to the formaldehyde. We found that the loss was not significant (\<2\%). Concerning the mean values of the lead concentration measured in the contaminated soft tissues, in liver they range from 6 to 22μgg(-1), and in kidneys from 44 to 79μgg(-1). The control rats show, in general, values below the EDXRF detection limit (2μgg(-1)). The ratio kidney/liver ranges from 2 to 10 and is strongly positively correlated with the age of the animals. A Spearman correlation matrix to investigate the correlation between elemental concentrations and the dependence of these concentrations with age showed that there is a strong positive correlation with age for lead in the liver but not in the kidney. The correlation matrix showed also that the concentration of lead in these two soft tissues is not correlated. The lead accumulation in liver is made by different plateaus that strongly decrease with age. It was verified the existence of two levels of accumulation in kidney, not very highlighted, which might be indicative of a maximum accumulation level for lead in kidney.

}, url = {http://www.sciencedirect.com/science/article/pii/S0946672X12000090}, author = {Guimar{\~a}es, Diana and Carvalho, Maria Luisa and Geraldes, Vera and Rocha, Isabel and Alves, Lu{\'\i}s Cerqueira and Santos, Jose Paulo} } @article {8119, title = {Lead in liver and kidney of exposed rats: Aging accumulation study.}, journal = {Journal of Trace Elements in Medicine and Biology}, volume = {26}, year = {2012}, note = {n/a}, month = {Oct}, pages = {285}, abstract = {

The concentration of lead in liver and kidneys of Wistar rats, fed with lead since fetal period in relation to their age and to a control group, was determined. A group of rats was exposed to lead acetate (n=30) in drinking water and the other group was exposed to normal water (n=20). Samples were collected from rats aging between 1 and 11 months and were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) without any chemical preparation. The EDXRF results were assessed by the PIXE (Proton Induced X-ray Emission) technique. The formaldehyde used to preserve the samples was also analyzed by ETAAS (Electro-Thermal Atomic Absorption Spectrometry) in order to verify if there was any loss of lead from the samples to the formaldehyde. We found that the loss was not significant (\<2\%). Concerning the mean values of the lead concentration measured in the contaminated soft tissues, in liver they range from 6 to 22μgg(-1), and in kidneys from 44 to 79μgg(-1). The control rats show, in general, values below the EDXRF detection limit (2μgg(-1)). The ratio kidney/liver ranges from 2 to 10 and is strongly positively correlated with the age of the animals. A Spearman correlation matrix to investigate the correlation between elemental concentrations and the dependence of these concentrations with age showed that there is a strong positive correlation with age for lead in the liver but not in the kidney. The correlation matrix showed also that the concentration of lead in these two soft tissues is not correlated. The lead accumulation in liver is made by different plateaus that strongly decrease with age. It was verified the existence of two levels of accumulation in kidney, not very highlighted, which might be indicative of a maximum accumulation level for lead in kidney.

}, url = {http://www.sciencedirect.com/science/article/pii/S0946672X12000090}, author = {Guimar{\~a}es, Diana and Carvalho, Maria Luisa and Geraldes, Vera and Rocha, Isabel and Alves, Lu{\'\i}s Cerqueira and Santos, Jose Paulo} } @article {2896, title = {Parametrization of the angular correlation and degree of linear polarization in two-photon decays of hydrogenlike ions}, journal = {Phys. Rev. A}, volume = {86}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Oct}, pages = {042509}, abstract = {

The spontaneous two-photon emission in hydrogenlike ions is investigated within the framework of second- order perturbation theory and Dirac{\textquoteright}s equation. Special attention is paid to the angular correlation of the emitted photons as well as to the degree of linear polarization of one of the two photons, if the second is just observed under arbitrary angles. Expressions for the angular correlation and the degree of linear polarization are expanded in powers of cosine functions of the two-photon opening angle, whose coefficients depend on the atomic number and the energy sharing of the emitted photons. The effects of including higher (electric and magnetic) multipoles upon the emitted photon pairs beyond the electric-dipole approximation are also discussed. Calculations of the coefficients are performed for the transitions 2s1/2 {\textrightarrow} 1s1/2, 3d3/2 {\textrightarrow} 1s1/2, and 3d5/2 {\textrightarrow} 1s1/2, along the entire hydrogen isoelectronic sequence (1

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.042509}, author = {P Amaro and F. Fratini and S. Fritzsche and P. Indelicato and J P Santos and A. Surzhykov} } @article {8144, title = {Parametrization of the angular correlation and degree of linear polarization in two-photon decays of hydrogenlike ions}, journal = {Physical Review A}, volume = {86}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Oct}, pages = {042509}, abstract = {

The spontaneous two-photon emission in hydrogenlike ions is investigated within the framework of second- order perturbation theory and Dirac{\textquoteright}s equation. Special attention is paid to the angular correlation of the emitted photons as well as to the degree of linear polarization of one of the two photons, if the second is just observed under arbitrary angles. Expressions for the angular correlation and the degree of linear polarization are expanded in powers of cosine functions of the two-photon opening angle, whose coefficients depend on the atomic number and the energy sharing of the emitted photons. The effects of including higher (electric and magnetic) multipoles upon the emitted photon pairs beyond the electric-dipole approximation are also discussed. Calculations of the coefficients are performed for the transitions 2s1/2 {\textrightarrow} 1s1/2, 3d3/2 {\textrightarrow} 1s1/2, and 3d5/2 {\textrightarrow} 1s1/2, along the entire hydrogen isoelectronic sequence (1 Z 100).

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.042509}, author = {P Amaro and F. Fratini and S. Fritzsche and P. Indelicato and J P Santos and A. Surzhykov} } @article {2898, title = {Relativistic polarization analysis of Rayleigh scattering by atomic hydrogen}, journal = {Phys. Rev. A}, volume = {86}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Oct}, pages = {043405}, abstract = {

A relativistic analysis of the polarization properties of light elastically scattered by atomic hydrogen is performed, based on the Dirac equation and second-order perturbation theory. The relativistic atomic states used for the calculations are obtained by making use of the finite basis set method and are expressed in terms of B splines and B polynomials. We introduce two experimental scenarios in which the light is circularly and linearly polarized, respectively. For each of these scenarios, the polarization-dependent angular distribution and the degrees of circular and linear polarization of the scattered light are investigated as a function of scattering angle and photon energy. Analytical expressions are derived for the polarization-dependent angular distribution which can be used for scattering by both hydrogenic as well as many-electron systems. Detailed computations are performed for Rayleigh scattering by atomic hydrogen within the incident photon energy range 0.5 to 5 keV. Particular attention is paid to the effects that arise from higher (nondipole) terms in the expansion of the electron-photon interaction.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.043405}, author = {Safari, L and P Amaro and S. Fritzsche and J P Santos and Tashenov, S and F. Fratini} } @article {8115, title = {Relativistic polarization analysis of Rayleigh scattering by atomic hydrogen}, journal = {Physical Review A}, volume = {86}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Oct}, pages = {043405}, abstract = {

A relativistic analysis of the polarization properties of light elastically scattered by atomic hydrogen is performed, based on the Dirac equation and second-order perturbation theory. The relativistic atomic states used for the calculations are obtained by making use of the finite basis set method and are expressed in terms of B splines and B polynomials. We introduce two experimental scenarios in which the light is circularly and linearly polarized, respectively. For each of these scenarios, the polarization-dependent angular distribution and the degrees of circular and linear polarization of the scattered light are investigated as a function of scattering angle and photon energy. Analytical expressions are derived for the polarization-dependent angular distribution which can be used for scattering by both hydrogenic as well as many-electron systems. Detailed computations are performed for Rayleigh scattering by atomic hydrogen within the incident photon energy range 0.5 to 5 keV. Particular attention is paid to the effects that arise from higher (nondipole) terms in the expansion of the electron-photon interaction.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.86.043405}, author = {Safari, L and P Amaro and S. Fritzsche and J P Santos and Tashenov, S and F. Fratini} } @article {2901, title = {Relativistic total cross section and angular distribution for Rayleigh scattering by atomic hydrogen}, journal = {Phys. Rev. A}, volume = {85}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {May}, pages = {043406}, abstract = {

We study the total cross section and angular distribution in Rayleigh scattering by hydrogen atom in the ground state, within the framework of Dirac relativistic equation and second-order perturbation theory. The relativistic states used for the calculations are obtained by making use of the finite basis-set method and expressed in terms of B splines and B polynomials. We pay particular attention to the effects that arise from higher (nondipole) terms in the expansion of the electron-photon interaction. It is shown that the angular distribution of scattered photons, while symmetric with respect to the scattering angle θ=90o within the electric dipole approximation, becomes asymmetric when higher multipoles are taken into account. The analytical expression of the angular distribution is parametrized in terms of Legendre polynomials. Detailed calculations are performed for photons in the energy range 0.5 to 10 keV. When possible, results are compared with previous calculations.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.85.043406}, author = {Safari, L and P Amaro and S. Fritzsche and J P Santos and F. Fratini} } @article {2900, title = {Absolute Measurement of the Relativistic Magnetic Dipole Transition Energy in Heliumlike Argon}, journal = {Phys. Rev. Lett.}, volume = {109}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Jul}, pages = {043005}, abstract = {

The 1s2s 3S1 ! 1s2 1S0 relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.

}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.109.043005}, author = {Amaro, Pedro and Schlesser, Sophie and Guerra, Mauro and Le Bigot, Eric-Olivier and Isac, Jean-Michel and Travers, Pascal and Santos, Jose Paulo and Szabo, Csilla and Gumberidze, Alexandre and Indelicato, Paul} } @article {8080, title = {Absolute Measurement of the Relativistic Magnetic Dipole Transition Energy in Heliumlike Argon}, journal = {Physical Review Letters}, volume = {109}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Jul}, pages = {043005}, abstract = {

The 1s2s 3S1 - 1s2 1S0 relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.

}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.109.043005}, author = {Amaro, Pedro and Schlesser, Sophie and Guerra, Mauro and Le Bigot, Eric-Olivier and Isac, Jean-Michel and Travers, Pascal and Santos, Jose Paulo and Szabo, Csilla and Gumberidze, Alexandre and Indelicato, Paul} } @article {8142, title = {Relativistic total cross section and angular distribution for Rayleigh scattering by atomic hydrogen}, journal = {Physical Review A}, volume = {85}, year = {2012}, note = {

PTDC/FIS/117606/2010

}, month = {Apr}, pages = {043406}, abstract = {

We study the total cross section and angular distribution in Rayleigh scattering by hydrogen atom in the ground state, within the framework of Dirac relativistic equation and second-order perturbation theory. The relativistic states used for the calculations are obtained by making use of the finite basis-set method and expressed in terms of B splines and B polynomials. We pay particular attention to the effects that arise from higher (nondipole) terms in the expansion of the electron-photon interaction. It is shown that the angular distribution of scattered photons, while symmetric with respect to the scattering angle θ=90o within the electric dipole approximation, becomes asymmetric when higher multipoles are taken into account. The analytical expression of the angular distribution is parametrized in terms of Legendre polynomials. Detailed calculations are performed for photons in the energy range 0.5 to 10 keV. When possible, results are compared with previous calculations.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.85.043406}, author = {Safari, L and P Amaro and S. Fritzsche and J P Santos and F. Fratini} } @article {193, title = {Calculation of two-photon decay rates of hydrogen-like ions by using B-polynomials}, journal = {Journal of Physics A: Mathematical and Theoretical}, volume = {44}, number = {24}, year = {2011}, pages = {245302}, abstract = {A new approach is laid out to investigate two-photon atomic transitions. It is based on the application of the finite-basis solutions constructed from the Bernstein polynomial (B-polynomial) sets. We show that such an approach provides a very promising route for the relativistic second-order (and even higher-order) calculations since it allows for analytical evaluation of the involved matrices elements. In order to illustrate possible applications of the method and to verify its accuracy, detailed calculations are performed for the 2 s 1/2 {\quotesinglbase}{\"U}{\'\i} 1 s 1/2 transition in neutral hydrogen and hydrogen-like ions, which are compared with the theoretical predictions based on the well-established B-spline basis-set approach.}, doi = {DOI: 10.1088/1751-8113/44/24/245302}, url = {http://stacks.iop.org/1751-8121/44/i=24/a=245302}, author = {P Amaro and A. Surzhykov and F. Parente and P. Indelicato and J P Santos} } @article {8139, title = {Calculation of two-photon decay rates of hydrogen-like ions by using B-polynomials}, journal = {Journal of Physics A: Mathematical and Theoretical}, volume = {44}, number = {24}, year = {2011}, note = {

Webpage CFA-FCTUNLJPS-Ref50

}, pages = {245302}, abstract = {

A new approach is laid out to investigate two-photon atomic transitions. It is based on the application of the finite-basis solutions constructed from the Bernstein polynomial (B-polynomial) sets. We show that such an approach provides a very promising route for the relativistic second-order (and even higher-order) calculations since it allows for analytical evaluation of the involved matrices elements. In order to illustrate possible applications of the method and to verify its accuracy, detailed calculations are performed for the 2 s 1/2 {\quotesinglbase}{\"U}{\'\i} 1 s 1/2 transition in neutral hydrogen and hydrogen-like ions, which are compared with the theoretical predictions based on the well-established B-spline basis-set approach.

}, url = {http://stacks.iop.org/1751-8121/44/i=24/a=245302}, author = {P Amaro and A. Surzhykov and F. Parente and P. Indelicato and J P Santos} } @article {707, title = {Two-photon absorption of few-electron heavy ions}, journal = {Physical Review A}, volume = {84}, year = {2011}, note = {

Copyright (C) 2010 The American Physical SocietyPlease report any problems to prola@aps.orgPRAWebpage CFA-FCTUNL

}, pages = {022511}, publisher = {American Physical Society}, abstract = {

The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac{\textquoteright}s relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.

}, keywords = {PACS: 32.90.+a, 32.80.Rm, 32.80.Wr, 31.10.+z}, url = {http://link.aps.org/doi/10.1103/PhysRevA.84.022511}, author = {A. Surzhykov and P. Indelicato and J P Santos and P Amaro and Th St{\"o}hlker and S. Fritzsche} } @article {8122, title = {Two-photon absorption of few-electron heavy ions}, journal = {Physical Review A}, volume = {84}, year = {2011}, note = {

Copyright (C) 2010 The American Physical SocietyPlease report any problems to prola@aps.orgPRAWebpage CFA-FCTUNLJPS-Ref46

}, pages = {022511}, publisher = {American Physical Society}, abstract = {

The two-photon absorption of few-electron ions has been studied by using second-order perturbation theory and Dirac\'s relativistic equation. Within this framework, the general expressions for the excitation cross sections and rates are derived including a full account of the higher-order multipole terms in the expansion of the electron-photon interaction. While these expressions can be applied to any ion, independent of its particular shell structure, detailed computations are carried out for the two-photon absorption of hydrogen-, helium-, and berylliumlike ions and are compared with the available theoretical and experimental data. The importance of relativistic and nondipole effects in the analysis and computation of induced two-photon transitions is pointed out. Moreover, we discuss the potential of these transitions for atomic parity-violation studies in the high-Z domain.

}, url = {http://link.aps.org/doi/10.1103/PhysRevA.84.022511}, author = {A. Surzhykov and P. Indelicato and J P Santos and P Amaro and Th St{\"o}hlker and S. Fritzsche} } @article {200, title = {Negative-continuum effects on the two-photon decay rates of hydrogenlike ions}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, volume = {80}, number = {5}, year = {2009}, pages = {052511}, abstract = {Two-photon decay of hydrogenlike ions is studied within the framework of second-order perturbation theory, based on the relativistic Dirac{\textquoteright}s equation. Special attention is paid to the effects arising from the summation over the negative-energy (intermediate virtual) states that occur in such a framework. In order to investigate the role of these states, detailed calculations have been carried out for the 2s1/2{\textendash}>1s1/2 and 2p1/2{\textendash}>1s1/2 transitions in neutral hydrogen H as well as for hydrogenlike xenon Xe53+ and uranium U91+ ions. We found that for a correct evaluation of the total and energy-differential decay rates, summation over the negative-energy part of Dirac{\textquoteright}s spectrum should be properly taken into account both for high-Z and low-Z atomic systems.}, keywords = {atomic structure Dirac equation hydrogen neutral atoms perturbation theory relativistic corrections spontaneous emission uranium xenon}, doi = {DOI: 10.1103/PhysRevA.80.052511}, url = {http://link.aps.org/abstract/PRA/v80/e052511}, author = {A. Surzhykov and J P Santos and P Amaro and P. Indelicato} } @article {8123, title = {Negative-continuum effects on the two-photon decay rates of hydrogenlike ions}, journal = {Physical Review A}, volume = {80}, number = {5}, year = {2009}, note = {

Webpage CFA-FCTUNLJPS-Ref39

}, pages = {052511}, publisher = {APS}, abstract = {

Two-photon decay of hydrogenlike ions is studied within the framework of second-order perturbation theory, based on the relativistic Dirac\'s equation. Special attention is paid to the effects arising from the summation over the negative-energy (intermediate virtual) states that occur in such a framework. In order to investigate the role of these states, detailed calculations have been carried out for the 2s1/2--\>1s1/2 and 2p1/2--\>1s1/2 transitions in neutral hydrogen H as well as for hydrogenlike xenon Xe53+ and uranium U91+ ions. We found that for a correct evaluation of the total and energy-differential decay rates, summation over the negative-energy part of Dirac\'s spectrum should be properly taken into account both for high-Z and low-Z atomic systems.

}, url = {http://link.aps.org/abstract/PRA/v80/e052511}, author = {A. Surzhykov and J P Santos and P Amaro and P. Indelicato} } @article {202, title = {Resonance effects on the two-photon emission from hydrogenic ions}, journal = {Physical Review A (Atomic, Molecular, and Optical Physics)}, volume = {79}, number = {6}, year = {2009}, pages = {062504}, abstract = {A theoretical study of the all two-photon transitions from initial bound states with ni=2,3 in hydrogenic ions is presented. High-precision values of relativistic decay rates for ions with nuclear charge in the range 1<=Z<=92 are obtained through the use of finite basis sets for the Dirac equation constructed from B splines. We also report the spectral (energy) distributions of several resonant transitions, which exhibit interesting structures, such as zeros in the emission spectrum, indicating that two-photon emission is strongly suppressed at certain frequencies. We compare two different approaches (the line profile approach and the QED approach based on the analysis of the relativistic two-loop self-energy) to regularize the resonant contribution to the decay rate. Predictions for the pure two-photon contributions obtained in these approaches are found to be in good numerical agreement.}, keywords = {bound states Dirac equation quantum electrodynamics radiative lifetimes two-photon processes}, doi = {DOI: 10.1103/PhysRevA.79.062504}, url = {http://link.aps.org/abstract/PRA/v79/e06250}, author = {P Amaro and J P Santos and F. Parente and A. Surzhykov and P. Indelicato} } @article {8141, title = {Resonance effects on the two-photon emission from hydrogenic ions}, journal = {Physical Review A}, volume = {79}, number = {6}, year = {2009}, note = {

Webpage CFA-FCTUNLJPS-Ref36

}, pages = {062504}, abstract = {

A theoretical study of the all two-photon transitions from initial bound states with ni=2,3 in hydrogenic ions is presented. High-precision values of relativistic decay rates for ions with nuclear charge in the range 1\<=Z\<=92 are obtained through the use of finite basis sets for the Dirac equation constructed from B splines. We also report the spectral (energy) distributions of several resonant transitions, which exhibit interesting structures, such as zeros in the emission spectrum, indicating that two-photon emission is strongly suppressed at certain frequencies. We compare two different approaches (the line profile approach and the QED approach based on the analysis of the relativistic two-loop self-energy) to regularize the resonant contribution to the decay rate. Predictions for the pure two-photon contributions obtained in these approaches are found to be in good numerical agreement.

}, url = {http://journals.aps.org/pra/abstract/10.1103/PhysRevA.79.062504}, author = {P Amaro and J P Santos and F. Parente and A. Surzhykov and P. Indelicato} } @article {217, title = {Contrasting Behavior in Azide Pyrolyses: An Investigation of the Thermal Decompositions of Methyl Azidoformate, Ethyl Azidoformate and 2-Azido-N, N-dimethylacetamide by Ultraviolet Photoelectron Spectroscopy and Matrix Isolation Infrared Spectroscopy}, journal = {Chemistry - A European Journal}, volume = {11}, number = {5}, year = {2005}, note = {10.1002/chem.200400767 About DOI}, pages = {1665-1676}, abstract = {The thermal decompositions of methyl azidoformate (N3COOMe), ethyl azidoformate (N3COOEt) and 2-azido-N,N-dimethylacetamide (N3CH2CONMe2) have been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. N2 appears as an initial pyrolysis product in all systems, and the principal interest lies in the fate of the accompanying organic fragment. For methyl azidoformate, four accompanying products were observed: HNCO, H2CO, CH2NH and CO2, and these are believed to arise as a result of two competing decomposition routes of a four-membered cyclic intermediate. Ethyl azidoformate pyrolysis yields four corresponding products: HNCO, MeCHO, MeCHNH and CO2, together with the five-membered-ring compound 2-oxazolidone. In contrast, the initial pyrolysis of 2-azido-N,N-dimethyl acetamide, yields the novel imine intermediate Me2NCOCHNH, which subsequently decomposes into dimethyl formamide (HCONMe2), CO, Me2NH and HCN. This intermediate was detected by matrix isolation IR spectroscopy, and its identity confirmed both by a molecular orbital calculation of its IR spectrum, and by the temperature dependence and distribution of products in the PES and IR studies. Mechanisms are proposed for the formation and decomposition of all the products observed in these three systems, based on the experimental evidence and the results of supporting molecular orbital calculations.}, keywords = {azides IR spectroscopy matrix isolation photoelectron spectrosopy}, author = {J. M. Dyke and G. Levita and A. Morris and J. S. Ogden and A. A. Dias and M. Algarra and J P Santos and M. L. Costa and P. Rodrigues and M. M. Andrade and M. T. Barros} } @article {8125, title = {Contrasting Behavior in Azide Pyrolyses: An Investigation of the Thermal Decompositions of Methyl Azidoformate, Ethyl Azidoformate and 2-Azido-N, N-dimethylacetamide by Ultraviolet Photoelectron Spectroscopy and Matrix Isolation Infrared Spectroscopy}, journal = {Chemistry - A European Journal}, volume = {11}, number = {5}, year = {2005}, note = {

10.1002/chem.200400767 About DOIJPS-Ref25

}, pages = {1665-1676}, abstract = {

The thermal decompositions of methyl azidoformate (N3COOMe), ethyl azidoformate (N3COOEt) and 2-azido-N,N-dimethylacetamide (N3CH2CONMe2) have been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. N2 appears as an initial pyrolysis product in all systems, and the principal interest lies in the fate of the accompanying organic fragment. For methyl azidoformate, four accompanying products were observed: HNCO, H2CO, CH2NH and CO2, and these are believed to arise as a result of two competing decomposition routes of a four-membered cyclic intermediate. Ethyl azidoformate pyrolysis yields four corresponding products: HNCO, MeCHO, MeCHNH and CO2, together with the five-membered-ring compound 2-oxazolidone. In contrast, the initial pyrolysis of 2-azido-N,N-dimethyl acetamide, yields the novel imine intermediate Me2NCOCHNH, which subsequently decomposes into dimethyl formamide (HCONMe2), CO, Me2NH and HCN. This intermediate was detected by matrix isolation IR spectroscopy, and its identity confirmed both by a molecular orbital calculation of its IR spectrum, and by the temperature dependence and distribution of products in the PES and IR studies. Mechanisms are proposed for the formation and decomposition of all the products observed in these three systems, based on the experimental evidence and the results of supporting molecular orbital calculations.

}, author = {J. M. Dyke and G. Levita and A. Morris and J. S. Ogden and A. A. Dias and M. Algarra and J P Santos and M. L. Costa and P. Rodrigues and M. M. Andrade and M. T. Barros} } @article {8132, title = {A Study of the Thermal Decomposition of 2-Azidoacetamide by Ultraviolet Photoelectron Spectroscopy and Matrix-Isolation Infrared Spectroscopy: Identification of the Imine Intermediate H2NCOCHNH}, journal = {The Journal of Physical Chemistry A}, volume = {108}, number = {25}, year = {2004}, note = {

DOI: 10.1021/jp031288sJPS-Ref21

}, pages = {5299-5307}, publisher = {American Chemical Society}, abstract = {

The thermal decomposition of 2-azidoacetamide (N3CH2CONH2) has been studied by matrix-isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. N2, CH2NH, HNCO, CO, NH3, and HCN are observed as high-temperature decomposition products, while at lower temperatures, the novel imine intermediate H2NCOCHNH is observed in the matrix-isolation IR experiments. The identity of this intermediate is confirmed both by ab initio molecular orbital calculations of its IR spectrum and by the temperature dependence and distribution of products in the photoelectron spectroscopy (PES) and IR studies. Mechanisms are proposed for the formation and decomposition of the intermediate consistent both with the observed results and with estimated activation energies based on pathway calculations.

}, url = {http://dx.doi.org/10.1021/jp031288s}, author = {J. M. Dyke and G. Levita and A. Morris and J. S. Ogden and A. A. Dias and M. Algarra and J P Santos and M. L. Costa and P. Rodrigues and M. T. Barros} }