Optical and generalized oscillator strengths for inner-shell excitations in Ar and CO 2

Abstract

We have determined theoretical values for the transition energies, optical oscillator strengths and generalized oscillator strengths (GOSs) of the following inner-shell excitations: (a) 1P 1 ← X 1S 0 (2p → 4s) in the Ar atom; (b) 1Π u ← X 1Σ g +[C 1s(2σ g) → 2π u] in the CO 2 molecule; (c) 1Π u ← X 1Σ g +[O 1s(1σ g) → 2π u] in the CO 2 molecule; (d) 1Π g → X 1Σ g +[O 1s(1σ u) ← 2π u] in the CO 2 molecule. The influence of relaxation, correlation and (for the O 1s excitations) hole localization effects on these properties was studied. For this purpose the target wavefunctions for each state were determined at the Hartree—Fock, configuration interaction and (in the case of O 1s excitations in the CO 2 molecule) generalized multistructural levels. The first Born approximation was used in the calculation of the GOSs.