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C
Amaro, P., A. Surzhykov, F. Parente, P. Indelicato, and J. P. Santos. "Calculation of two-photon decay rates of hydrogen-like ions by using B-polynomials." Journal of Physics A: Mathematical and Theoretical 44 (2011): 245302. AbstractWebsite

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 ‚Üí 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.

Sampaio, J. M., M. Guerra, F. Parente, T. I. Madeira, P. Indelicato, J. P. Santos, and J. P. Marques. "Calculations of photo-induced X-ray production cross-sections in the energy range 1–150 keV and average fluorescence yields for Zn, Cd and Hg." Atomic Data and Nuclear Data Tables 111-112 (2016): 67-86. AbstractWebsite

Atomic Data and Nuclear Data Tables, 111-112 (2016) 67-86. doi:10.1016/j.adt.2016.02.001

Pessanha, S., C. Fonseca, J. P. Santos, M. L. Carvalho, and A. A. Dias. "Comparison of standard-based and standardless methods of quantification used in X-ray fluorescence analysis: Application to the exoskeleton of clams." X-Ray Spectrom. 47 (2018): 108-115. Abstract

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Grilo, Filipe, Chintan Shah, Steffen Kühn, René Steinbrügge, Keisuke Fujii, José Marques, Ming Feng Gu, José Paulo Santos, José Crespo R. López-Urrutia, and Pedro Amaro. "Comprehensive Laboratory Measurements Resolving the {LMM} Dielectronic Recombination Satellite Lines in Ne-like Fe xvii Ions." The Astrophysical Journal 913 (2021): 140. AbstractWebsite
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Pinto, R. M., A. A. Dias, M. L. Costa, and J. P. Santos. "Computational study on the ionization energies of benzyl azide and its methyl derivatives." Journal of Molecular Structure: THEOCHEM 948 (2010): 15-20. AbstractWebsite
Ionization energies of benzyl azide (BA), C6H5CH2N3, its methyl derivatives, 2-, 3- and 4-methyl benzyl azide and (1-azidoethyl)benzene (2-, 3- and 4-MBA and 1-AEB), (CH3)C6H4CH2 N3, have been calculated with several basis sets, with M¯ller-Plesset and Hartree-Fock methods. The data are compared to the ionizations energies obtained from HeI photoelectron spectroscopy (UVPES) experiments, in order to support the correct assignment of the bands. The nature and character of the molecular orbitals are also discussed.
Pinto, R. M., A. A. Dias, M. L. Costa, and J. P. Santos. "Computational study on the ionization energies of benzyl azide and its methyl derivatives." Journal of Molecular Structure: THEOCHEM 948 (2010): 15-20. AbstractWebsite

Ionization energies of benzyl azide (BA), C6H5CH2N3, its methyl derivatives, 2-, 3- and 4-methyl benzyl azide and (1-azidoethyl)benzene (2-, 3- and 4-MBA and 1-AEB), (CH3)C6H4CH2 N3, have been calculated with several basis sets, with M¯ller-Plesset and Hartree-Fock methods. The data are compared to the ionizations energies obtained from HeI photoelectron spectroscopy (UVPES) experiments, in order to support the correct assignment of the bands. The nature and character of the molecular orbitals are also discussed.

Dyke, J. M., G. Levita, A. Morris, J. S. Ogden, A. A. Dias, M. Algarra, J. P. Santos, M. L. Costa, P. Rodrigues, M. M. Andrade, and M. T. Barros. "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." Chemistry - A European Journal 11 (2005): 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.
Dyke, J. M., G. Levita, A. Morris, J. S. Ogden, A. A. Dias, M. Algarra, J. P. Santos, M. L. Costa, P. Rodrigues, M. M. Andrade, and M. T. Barros. "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." Chemistry - A European Journal 11 (2005): 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.

Santos, J. P., F. Parente, and Y. K. Kim. "Cross sections for K-shell ionization of atoms by electron impact." Journal of Physics B: Atomic and Molecular Physics 36 (2003): 4211-4224. AbstractWebsite

The relativistic version of the binary-encounter Bethe (BEB) model is used to calculate cross sections for K-shell ionization of atoms by electron impact. The BEB model requires only two atomic constants, the binding energy and kinetic energy of the K electrons. These constants are listed for carbon to antimony. Comparisons with available experimental data on N, O, Na, Al, Cl, Ca, Cu, Se and Sb show good agreement. The K-shell ionization cross sections for C, Mg, P, S, Cr, As and Cd are tabulated.

Wain, Alison, Diogo Castro, {Maria Fernanda} Rollo, Frederico Nogueira, Gon{\c c}alo Santos, {Maria Gra{\c da c}a} Filipe, Isabel Tissot, {Jorge Miguel} Sampaio, {José Paulo} Santos, Manuel Lemos, Marta Manso, Matthias Tissot, Mauro Guerra, Miles Oglethorpe, Pedro Amaro, Pedro Pedroso, Rui Silva, Sofia Pessanha, and {Tiago A. N. } Silva. Cultura Material, Cultura Científica: Património Industrial para o Futuro. Portugal: Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2021. Abstract

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

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Marques, J., F. Parente, A. Costa, M. Martins, P. Indelicato, and J. P. Santos. "Decay of the 1s^{2}2s3p ^{3}P_{0} level in Be-like ions." Phys. Rev. A 86 (2012): 052521. AbstractWebsite

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Pessanha, Sofia, Ana Samouco, Ricardo Adão, Maria Luisa Carvalho, Jose Paulo Santos, and Pedro Amaro. "Detection limits evaluation of a portable energy dispersive X-ray fluorescence setup using different filter combinations." X-Ray Spectrometry 46 (2017): 102-106. AbstractWebsite

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,...

Cardoso, Pedro, Pedro Amaro, Jose Paulo Santos, Joaquim T. de Assis, and Maria Luisa Carvalho. "Determination of Nickel and Manganese Contaminants in Pharmaceutical Iron Supplements Using Energy Dispersive X-ray Fluorescence." Applied Spectroscopy 71 (2017): 432-437. AbstractWebsite
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Cardoso, Pedro, Pedro Amaro, Jose Paulo Santos, Joaquim T. de Assis, and Maria Luisa Carvalho. "Determination of Nickel and Manganese Contaminants in Pharmaceutical Iron Supplements using Energy Dispersive X-ray Fluorescence." Applied Spectroscopy (2016). AbstractWebsite

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 fólico (iron gylcinate), Anemifer (iron(II) sulfate monohydrate), Noripurum (iron(III)-hydroxide polymaltose complex), Sulferbel (iron(II) sulfate monohydrate), and Combiron Fólico (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.

Rahangdale, H. V., M. Guerra, P. K. Das, S. De, J. P. Santos, D. Mitra, and S. Saha. "Determination of subshell-resolved <span class="aps-inline-formula"><math><mi>L</mi></math></span>-shell-ionization cross sections of gold induced by 15–40-keV electrons." Physical Review A 89 (2014): 052708. AbstractWebsite
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Rahangdale, H. V., M. Guerra, P. K. Das, S. De, J. P. Santos, D. Mitra, and S. Saha. "Determination of subshell-resolved <span class="aps-inline-formula"><math><mi>L</mi></math></span>-shell-ionization cross sections of gold induced by 15–40-keV electrons." Physical Review A 89 (2014): 052708. AbstractWebsite
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Zeeshan, Faisal, Joanna Hoszowska, {Jean Claude} Dousse, Dimosthenis Sokaras, {Tsu Chien} Weng, Roberto Alonso-Mori, Matjaz Kav{\v c}i{\v c}, Mauro Guerra, {Jorge Miguel} Sampaio, Fernando Parente, Paul Indelicato, {José Pires} Marques, and {José Paulo} Santos. "Diagram, valence-to-core, and hypersatellite Kβ X-ray transitions in metallic chromium." X-Ray Spectrometry 48 (2019): 351-359. 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–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.

Sampaio, J. M., T. I. Madeira, M. Guerra, F. Parente, J. P. Santos, P. Indelicato, and J. P. Marques. "Dirac-Fock calculations of K−, L−, and M-shell fluorescence and Coster-Kronig yields for Ne, Ar, Kr, Xe, Rn, and Uuo." Physical Review A 91 (2015): 052507. AbstractWebsite
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Costa, A. M., M. C. Martins, J. P. Santos, P. Indelicato, and F. Parente. "Dirac-Fock Transition Energies and Radiative and Radiationless Transition Probabilities for Ar8+ to Ar16+ Ion Levels with K-Shell Hole." Atomic Data and Nuclear Data Tables 79 (2001): 223-239. Abstract
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Guerra, M., C. Ferreira, M. L. Carvalho, J. P. Santos, and S. Pessanha. "Distribution of toxic elements in teeth treated with amalgam using μ-energy dispersive X-ray fluorescence." Spectrochimica Acta Part B: Atomic Spectroscopy 122 (2016): 114-117. AbstractWebsite

Spectrochimica Acta Part B: Atomic Spectroscopy, 122 (2016) 114-117. doi:10.1016/j.sab.2016.06.006

Amaro, P., J. P. Marques, P. Indelicato, T. K. Mukherjee, J. K. Saha, L. C. Tribedi, and J. P. Santos. "Double KK excited states in highly charged sulphur." Journal of Physics: Conference Series 635 (2015): 022071. Abstract

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Guerra, M., F. Parente, and J. P. Santos. "Electron impact ionization cross sections of several ionization stages of Kr, Ar and Fe." International Journal of Mass Spectrometry 348 (2013): 1-8. AbstractWebsite

International Journal of Mass Spectrometry, 348 (2013) 1-8. doi:10.1016/j.ijms.2013.02.011

Guerra, M., F. Parente, and J. P. Santos. "Electron impact ionization cross sections of several ionization stages of Kr, Ar and Fe." International Journal of Mass Spectrometry 348 (2013): 1-8. AbstractWebsite

International Journal of Mass Spectrometry, 348 (2013) 1-8. doi:10.1016/j.ijms.2013.02.011

Guerra, M., Th Stöhlker, P. Amaro, J. Machado, and J. P. Santos. "Electron impact ionization cross-sections for few-electron uranium ions." Journal of Physics B: Atomic, Molecular and Optical Physics 48 (2015): 1-5. AbstractWebsite

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

Guerra, M., F. Parente, and J. P. Santos. "Electron impact ionization of atomic target inner-shells." Journal of Physics: Conference Series 194 (2009): 042047. AbstractWebsite
There is a need for reliable theoretical methods to calculate electron-impact total ionization cross sections for the large number of neutral atoms and ions with open shell structures. These cross sections are used in a wide range of scientific and industrial applications, such as astrophysical plasmas, atmospheric science, X-ray lasers, magnetic fusion, radiation physics, semiconductor fabrication, accelerator physics and tumor therapy physics. The binary-encounter-Bethe (BEB) model [1], using an analytic formula that requires only two atomic constants, the binding energy and kinetic energy of the electrons, generates direct ionization cross sections for any neutral atom (or molecule), which are reliable in intensity (15%) and shape from the ionization threshold to a few keV in the incident energy [3], or to thousands keV if we consider its relativistic version(RBEB) [2]. In this work we present K- and L-shell ionization cross sections calculations for heavy atoms.