Recent Publications

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2021
Krauth, Julian J., Karsten Schuhmann, Marwan Abdou Ahmed, Fernando D. Amaro, Pedro Amaro, François Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Marc Diepold, Luis M. P. Fernandes, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Jens Hartmann, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Yi-Wei Liu, Jorge Machado, Cristina M. B. Monteiro, Françoise Mulhauser, Boris Naar, Tobias Nebel, François Nez, Joaquim M. F. dos Santos, José Paulo Santos, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Jan Vogelsang, Andreas Voss, Birgit Weichelt, Randolf Pohl, Aldo Antognini, and Franz Kottmann. "Measuring the $\upalpha$-particle charge radius with muonic helium-4 ions." Nature 589 (2021): 527-531. AbstractWebsite
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Santos, J. P., Mauro Guerra, Jorge M. Sampaio, Gonçalo R. Vília, César A. Godinho, Daniel Pinheiro, Pedro Amaro, José P. Marques, Jorge Machado, Paul Indelicato, Fernando Parente, and José Paulo Santos. "Fundamental Parameters Related to Selenium K\alpha and K\beta Emission X-ray Spectra." Atoms (2021). AbstractWebsite
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2020
Ito, Y., T. Tochio, M. Yamashita, S. Fukushima, A. M. Vlaicu, J. P. Marques, J. M. Sampaio, M. Guerra, J. P. Santos, Ł. Syrocki, K. Słabkowska, E. WÈ©der, M. Polasik, J. Rzadkiewicz, P. Indelicato, Y. Ménesguen, M.-Ch. Lépy, and F. Parente. "Structure of K$\upalpha$1,2- and K$\upbeta$1,3-emission x-ray spectra for Se, Y, and Zr." Physical Review A 102 (2020). AbstractWebsite
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Santos, J. P., J. Machado, Guojie Bian, Nancy Paul, M. Trassinelli, P. Amaro, M. Guerra, C. I. Szabo, A. Gumberidze, J. M. Isac, J. P. Santos, J. P. Desclaux, and P. Indelicato. "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." Physical Review A (2020). AbstractWebsite
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2019
Marques, J. P., M. C. Martins, A. M. Costa, P. Indelicato, F. Parente, and J. P. Santos. "Theoretical determination of K X-ray transition energy and probability values for highly charged (He- through B-like) Nd, Sm, Gd, Dy, Er, and Yb ions." Radiat. Phys. Chem. 154 (2019): 17-20. Abstract

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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.

Ménesguen, Y., {M. C. } Lépy, Y. Ito, M. Yamashita, S. Fukushima, M. Polasik, K. Słabkowska, Syrocki, E. Wȩder, P. Indelicato, {J. P. } Marques, {J. M. } Sampaio, M. Guerra, F. Parente, and {J. P. } Santos. "Precise x-ray energies of gadolinium determined by a combined experimental and theoretical approach." Journal Of Quantitative Spectroscopy & Radiative Transfer 236 (2019). Abstract

We combined different experimental techniques with a theoretical approach to determine a consistent set of diagram lines energies and binding energies. We propose an original approach consisting in determining the mass attenuation coefficients in an energy range covering the L-, M- and N- absorption edges, including a detailed evaluation of the associated uncertainties, to derive precisely the binding energies. We investigated the Lα, Lβ and M spectra of Gd with an independantly calibrated high-resolution anti-parallel double-crystal x-ray spectrometer. All the lines were identified and found in excellent agreement with the binding energies previously derived. Morever, we identified for the first time M5−O2, M4−O2,3 and M4−N2,3 diagram lines.

2018
Ito, Y., T. Tochio, M. Yamashita, S. Fukushima, A. M. Vlaicu, Ł. Syrocki, K. Słabkowska, E. Weder, M. Polasik, K. Sawicka, P. Indelicato, J. P. Marques, J. M. Sampaio, M. Guerra, J. P. Santos, and F. Parente. "Structure of high-resolution K$\beta$1,3 x-ray emission spectra for the elements from Ca to Ge." Phys. Rev. A 97 (2018): 052505. Abstract

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Guerra, M., J. M. Sampaio, F. Parente, P. Indelicato, P. Hönicke, M. Muller, B. Beckhoff, J. P. Marques, and J. P. Santos. "{Theoretical and experimental determination of $K$- and $L$-shell x-ray relaxation parameters in Ni}." Phys. Rev. A 97 (2018): 042501. Abstract
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Ménesguen, Y., M. - C. Lépy, J. M. Sampaio, J. P. Marques, F. Parente, M. Guerra, P. Indelicato, J. P. Santos, P. Hönicke, and B. Beckhoff. "{A combined experimental and theoretical approach to determine X-ray atomic fundamental quantities of tin}." X-Ray Spectrom. 47 (2018): 341-351. Abstract
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Ménesguen, Y., M. - C. Lépy, J. M. Sampaio, J. P. Marques, F. Parente, M. Guerra, P. Indelicato, and J. P. Santos. "{Experimental and theoretical determination of the L-fluorescence yields of bismuth}." Metrologia 55 (2018): 621-630. Abstract
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Machado, J., C. I. Szabo, J. P. Santos, P. Amaro, M. Guerra, A. Gumberidze, Guojie Bian, J. M. Isac, and P. Indelicato. "{High-precision measurements of $n=2\rightarrow n=1$ transition energies and level widths in He- and Be-like argon ions}." Phys. Rev. 97 (2018): 032517. Abstract
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Monteiro, C. M. B., F. D. Amaro, M. S. Sousa, M. Abdou-Ahmed, P. Amaro, F. Biraben, T. Chen, D. S. Covita, A. J. Dax, M. Diepold, L. M. P. Fernandes, B. Franke, S. Galtier, A. L. Gouvêa, J. Götzfried, T. Graf, T. W. Hansch, M. Hildebrandt, P. Indelicato, L. Julien, K. Kirch, A. Knecht, F. Kottmann, J. J. Krauth, Y. Liu, J. Machado, F. Mulhauser, B. Naar, T. Nebel, F. Nez, R. Pohl, J. P. Santos, J. M. F. dos Santos, K. Schuhmann, C. I. Szabo, D. Taqqu, J. F. C. A. Veloso, and A. Antognini. "{On the double peak structure of avalanche photodiode response to monoenergetic x-rays at various temperatures and bias voltages}." J. Inst. 13 (2018): C01033. Abstract
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Amaro, Pedro, Ulisses Loureiro, Laleh Safari, Filippo Fratini, Paul Indelicato, Thomas Stohlker, and Jose Paulo Santos. "{Quantum interference in laser spectroscopy of highly charged lithiumlike ions}." Phys. Rev. A 97 (2018): 022510. Abstract
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2017
Santos, J. P., F. Parente, M. C. Martins, P. Indelicato, E. P. Benis, T. J. M. Zouros, and J. P. Marques. "Radiative transition rates of 1s2s(3S)3p levels for Li-like ions with 5 <= Z <= 10." Nuclear Inst. and Methods in Physics Research, B 408 (2017): 100-102. AbstractWebsite

Nuclear Inst. and Methods in Physics Research, B, 408 (2017) 100-102. doi:10.1016/j.nimb.2017.04.015

Pohl, Randolf, François Nez, Luis M. P. Fernandes, Marwan Abdou Ahmed, Fernando D. Amaro, Pedro Amaro, François Biraben, João M. R. Cardoso, Daniel S. Covita, Andreas Dax, Satish Dhawan, Marc Diepold, Beatrice Franke, Sandrine Galtier, Adolf Giesen, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Paul Knowles, Franz Kottmann, Julian J. Krauth, Eric-Olivier Le Bigot, Yi-Wei Liu, José A. M. Lopes, Livia Ludhova, Jorge Machado, Cristina M. B. Monteiro, Françoise Mulhauser, Tobias Nebel, Paul Rabinowitz, Joaquim M. F. dos Santos, Jose Paulo Santos, Lukas A. Schaller, Karsten Schuhmann, Catherine Schwob, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Andreas Voss, Birgit Weichelt, and Aldo Antognini. "Laser Spectroscopy of Muonic Atoms and Ions." In Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016), 1-12. Journal of the Physical Society of Japan, 2017. Abstract
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Guerra, M., P. Amaro, J. P. Santos, and P. Indelicato. "Relativistic calculations of screening parameters and atomic radii of neutral atoms." Atomic Data and Nuclear Data Tables 117-118 (2017): 439-457. AbstractWebsite

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

2016
Ito, Y., T. Tochio, H. Ohashi, M. Yamashita, S. Fukushima, M. Polasik, K. Słabkowska, Ł. Syrocki, E. Szymańska, J. Rzadkiewicz, P. Indelicato, J. P. Marques, M. C. Martins, J. P. Santos, and F. Parente. "Kα1,2x-ray linewidths, asymmetry indices, and [KM]shake probabilities in elements Ca to Ge and comparison with theory for Ca, Ti, and Ge." Physical Review A 94 (2016): 042506-11. AbstractWebsite
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Marques, J. P., P. Indelicato, F. Parente, J. M. Sampaio, and J. P. Santos. "Ground-state Landé <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>g</mi></math></span> factors for selected ions along the boron isoelectronic sequence." Physical Review A 94 (2016): 042504. AbstractWebsite

Land\'e $g$ factors for the fine-structure $1{s}^{2}2{s}^{2}2p\phantom{\rule{0.16em}{0ex}}^{2}P_{1/2}$ and $^{2}P_{3/2}$ levels in the boron isoelectronic sequence for selected $Z$ values have been calculated using the multiconfiguration Dirac-Fock method with both quantum-electrodynamic and electronic correlation corrections included. All-order Breit and vacuum polarization corrections were included in the calculation, with a fully optimized active set wave function. The results are compared with the available theoretical data, showing a very good agreement.

Marques, J. P., P. Indelicato, F. Parente, J. M. Sampaio, and J. P. Santos. "Ground-state Landé g factors for selected ions along the boron isoelectronic sequence." Physical Review A 94 (2016): 042504. AbstractWebsite

Land\'e $g$ factors for the fine-structure $1{s}^{2}2{s}^{2}2p\phantom{\rule{0.16em}{0ex}}^{2}P_{1/2}$ and $^{2}P_{3/2}$ levels in the boron isoelectronic sequence for selected $Z$ values have been calculated using the multiconfiguration Dirac-Fock method with both quantum-electrodynamic and electronic correlation corrections included. All-order Breit and vacuum polarization corrections were included in the calculation, with a fully optimized active set wave function. The results are compared with the available theoretical data, showing a very good agreement.

Sampaio, J. M., T. I. Madeira, M. Guerra, F. Parente, P. Indelicato, J. P. Santos, and J. P. Marques. "Relativistic calculations of K-, L- and M-shell X-ray production cross-sections by electron impact for Ne, Ar, Kr, Xe, Rn and Uuo." Journal of Quantitative Spectroscopy and Radiative Transfer 182 (2016): 87-93. AbstractWebsite

Journal of Quantitative Spectroscopy and Radiative Transfer, 182 + (2016) 87-93. doi:10.1016/j.jqsrt.2016.05.012

Amaro, Pedro, Filippo Fratini, Laleh Safari, Jorge Machado, Mauro Guerra, Paul Indelicato, and Jose Paulo Santos. "Relativistic evaluation of the two-photon decay of the metastable 1s22s2p 3P0 state in berylliumlike ions with an effective-potential model." Physical Review A 93 (2016): 032502-8. AbstractWebsite

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.

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

2015
Santos, J. P., J. P. Marques, M. C. Martins, P. Indelicato, E. P. Benis, T. J. M. Zouros, and F. Parente. "Energy levels, transition rates and lifetimes for Li-like ions with Z≤ 10 in the 1 s2 s( 3S)3ℓ states." Journal of Physics: Conference Series 635 (2015): 052060-2. AbstractWebsite
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Marques, J. P., M. Guerra, F. Parente, J. P. Santos, P. Indelicato, and J. M. Sampaio. "K-shell width, fluorescence yield, and Kβ/ Kαintensity ratio calculation for Fe in the Dirac-Fock approach." Journal of Physics: Conference Series 635 (2015): 092094-2. AbstractWebsite
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