Vibrational and electronic structure of the3d−1→4p(π,σ)−2normal Auger spectrum of HBr studied by fully relativistic configuration-interaction calculations

Abstract

Fully relativistic, self-consistent field calculations, based on the Dirac-Coulomb-Gaunt Hamiltonian, were performed on the ground state of HBr, the $\mathrm{Br}3d$--ionized ${\mathrm{HBr}}^{+},$ and the 4$p(\ensuremath{\pi},\ensuremath{\sigma}{)}^{\ensuremath{-}2}$ states of ${\mathrm{HBr}}^{2+}.$ Correlation in the ground and valence-excited states and partially in the $\mathrm{Br}3d$ ionized states was described using a configuration-interaction (CI) method. Calculated ionization energies and bond lengths were found to be in good agreement with recent experimental results. The distortion in the vibrational bands of the ${3d}^{\ensuremath{-}1}\ensuremath{\rightarrow}4p{\ensuremath{\pi}}^{\ensuremath{-}2}$ Auger transitions due to lifetime vibrational interference was verified through ab initio calculations. Bands due to the transitions to bound and continuum vibrational states of the same electronic state were reproduced by calculations and compared with experimentally determined profiles. The nonadiabatic effects in the spin-orbit-induced avoided level crossing were investigated using adiabatic and diabatic electronic basis sets.