José Paulo Santos

Energies and transition probabilities of Kβ hypersatellite lines are computed using the Dirac–Fock model for several values of Z throughout the periodic table. The influence of the Breit interaction on the energy shifts from the corresponding diagram lines and on the Kβh1/Kβh3 intensity ratio is evaluated. The widths of the double-K hole levels are calculated for Al and Sc. The results are compared to experiment and to other theoretical calculations.

Total electronic correlation corrections to the binding energies of the isoelectronic series of beryllium, neon, magnesium and argon, are calculated in the framework of relativistic multiconfiguration Dirac-Fock method. Convergence of the correlation energies is studied as the active set of orbitals is increased. The Breit interaction is treated fully self-consistently. The final results can be used in the accurately determination of atomic masses from highly charged ions data obtained in Penning-trap experiments.

Total electronic correlation corrections to the binding energies of the isoelectronic series of beryllium, neon, magnesium and argon, are calculated in the framework of relativistic multiconfiguration Dirac-Fock method. Convergence of the correlation energies is studied as the active set of orbitals is increased. The Breit interaction is treated fully self-consistently. The final results can be used in the accurately determination of atomic masses from highly charged ions data obtained in Penning-trap experiments.

In the present work we have calculated several relativistic transition probabilities for the F-like ions with 10 less-than-or-equals, slant Z less-than-or-equals, slant 49, in the framework of the Multi-Configuration Dirac–Fock method, for applications on laserphysics and astrophysics. The lines considered correspond to transitions between levels of 2p43s, 2p43p and 2p43d configurations. The spectral fine structure is taken into consideration and the results for individual lines are given.

In the present work we have calculated several relativistic transition probabilities for the F-like ions with 10 less-than-or-equals, slant Z less-than-or-equals, slant 49, in the framework of the Multi-Configuration Dirac–Fock method, for applications on laserphysics and astrophysics. The lines considered correspond to transitions between levels of 2p43s, 2p43p and 2p43d configurations. The spectral fine structure is taken into consideration and the results for individual lines are given.

Energies of two-electron one-photon transitions from initial double K-hole states were computed using the Dirac–Fock model. The transition energies of competing processes, the Ka hypersatellites, were also computed. The results are compared with experiment and to other theoretical calculations.

The determination of atomic masses from highly ionized atoms using Penning Traps requires precise values for electronic binding energies. In the present work, binding energies of several ions (from several elements) are calculated in the framework of two relativistic many-body methods: Relativistic Many-Body Perturbation Theory (RMBPT) and Multi-Configuration Dirac– Fock (MCDF). The ions studied in this work are: Cl (He and Li-like), Se (F and Ne-like), Cs (He, Be, Ne, Al, Cl, Ar, K, Kr, Xe-like and neutral Cs), Hg, Pb and U (Br and Kr-like). Some of them are presented in this paper. Cesium has been treated in more details, allowing for a systematic comparison between MCDF and RMBPT methods. The Cs ions binding energies allow for the determination of atomic Cs mass, which can be used in a QED-independent fine structure constant determination.

We present recent results in the field of total binding energy calculations, Landщ factors, quantum electrodynamics corrections and lifetime that are of interest for ion traps and ion sources. We describe in detail MCDF and RMBPT calculation of ionic binding energies, which are needed for the determination of atomic masses from highly charged ion measurements. We also show new results concerning Landщ factor in 3-electron ions. Finally we describe how relativistic calculations can help understand the physics of heavy ion production ion sources.

Radiationless transition rates to L1 vacancy states have been calculated ab initio in the Dirac-Fock approximation. The calculations include quantum-electrodynamic corrections. Results in the jj coupling scheme for all possible L1 transitions are tabulated for elements Yb and Hg.

n/a

We present theoretical results for the photoabsorption spectrum of an atom in parallel electric and magnetic fields, using the R-matrix method combined with quantum-defect theory. We introduce a radial basis set which is complete and orthonormal over a semi-infinite interval [r0,(infinity)), to allow calculations to be performed for high Rydberg states in nonhydrogenic atoms without encountering problems due to linear dependence of the basis set. The nonhydrogenic character of the spectra is analyzed for Li and Rb, and a comparison is made with previous high-precision experiments which shows that the theoretical results agree very well with experiment.

The magnitude of the time autocorrelation function M between states excited by two Gaussian laser pulses is calculated for both hydrogen and rubidium atoms inparallel electric and magnetic fields. M is determined by a full quantum-mechanical calculation but the peaks are identified with the periods of the shortest periodicorbits of the corresponding classical system. Qualitative agreement is obtained with experimental results, however, discrepancies are found in the relative heights ofthe peaks.