Pseudo-relativistic Hartree-Fock Research Articles

Autoionisation in copper vapour atoms: a study by ejected-electron spectroscopy following electron impact excitation

The autoionising energy levels of Cu atoms in the vapour phase have been investigated by ejected-electron spectroscopy. Following excitation by electron impact at 9-500 eV incident electron kinetic energy, autoionised electrons were detected with energies in the range 0-3.5 eV corresponding to 41 non-radiative transitions. The autoionising levels have been assigned with the aid of new ab initio pseudorelativistic Hartree-Fock calculations with configuration interaction, and by comparison with earlier photoabsorption data. For high incident electron energies, the observed autoionisation features are predominantly associated with decay of the Cu I 3d94snp (n=4, 5, 6 . . .) J=1/2, 3/2 levels to continua based on the Cu II ground state, although the absence of autoionising features whose energies exceed that of the Cu II 3d94s 3D3 final state indicates that when energetically permitted this is the preferred channel. At low incident electron energies, both parity-forbidden and J-forbidden levels are observed to autoionise.

Isotope shifts in the first and second spectra of barium: a comparison of pseudo-relativistic Hartree-Fock calculations with experimental results

The pseudo-relativistic Hartree-Fock model is used to calculate isotope shifts of Ba I and Ba II. A comparison with published results of recent shift measurements enables the latter to be divided into mass and field effects and shows that complex configuration interactions are present in Ba I. Overall, the agreement between theory and experiment is good, but some of the isotope shift results show that CI in Ba I is not yet completely understood.

Pseudo-relativistic screening ratios for Eu

Pseudo-relativistic Hartree-Fock calculations have been made for the configurations 4f76s2, 4f75d6s and 4f75d6p of Eu I, and for 4f76s and 4f75d of Eu II. These calculations have been used to provide ab initio estimates of screening effects and specific mass isotope shifts. Such estimates are in quite good accord with recent experimental results.

AB initio calculation of isotope shifts in CE II

Pseudo-relativistic Hartree-Fock calculations of the 4f 26s, 4f 26p, 4f 25d, 4f5d 2 and 4f5d6s configurations of Ce II have been used to provide estimates of screening effects and specific mass isotope shifts. It is shown that such estimates lie much closer to experimental values than those obtained from non-relativistic Hartree-Fock calculations.

AB initio calculation of isotope shifts in BaII

Hartree-Fock and pseudo-relativistic Hartree-Fock calculations have been made for the 6s, 5d and 6p configurations of BaII and used to provide estimates of screening effects and specific mass isotope shifts for the 6p-5d transition.