Inner-shell photoionization of ground-state lithium: Theoretical calculation in the photon energy region of hollow atomic states

Abstract

Photoion and photoelectron data for hollow lithium states were recently reported with increased spectral resolution. In order to reproduce and identify the important resonances due to 2lnЈlЈnЉlЉ 2 P o autoionizing states new photoionization calculations have been performed using the R-matrix code with a 29-term target representation for incident photon energies between 140 and 167 eV. Excellent agreement between theoretical and measured results over partial or total photoionization cross sections confirms the quality of the theoretical model. A determination of the resonance positions for each series converging to a 2l2lЈ 1,3 L threshold of Li is proposed.

Resonances in atomic photoionization

“…These resonances are investigated theoretically in Gou (1996) andin Vo Ky et al (1998b). For resonances below the Li þ 2s2p 3 P 0 threshold, the energies obtained from experiments agree reasonably well with those of Chung and Gou (1996).…”

“…For resonances below the Li þ 2s2p 3 P 0 threshold, the energies obtained from experiments agree reasonably well with those of Chung and Gou (1996). But, for resonances above the Li þ 2s2p 3 P 0 ; much discrepancies exists between experiments as well as theories (see Vo Ky et al, 1998b).…”

Resonant inelastic soft x-ray scattering at double core excitations in solid LiCl

“…Maintaining the atomic picture this implies that the two local electrons in the intermediate state principally have p and d symmetry, which leads to the notion that it is primarily pd double core excitons which are accompanied by a band excitation. Note also that for free ions the difference between 2l2lЈ and 2l3lЈ states is roughly 9 eV, 20 almost coinciding with the band gap in LiCl. This brings in the possibility of mixing with direct 2p3d-like excitations, which would be situated far up in the continuum.…”

“…This structure has two main components resonating at E 1 Ϸ 148. citation energy are close to the 1s 2 1 S → 2s2p 1 P transition in free Li + which is at 150.3 eV. 20,21 This makes it straightforward to assign these features to localized double excitations of the two Li 1s electrons. To separate the various types of excitations we use Greek letters for the first step of the scattering process and numerical subscripts for the emission step.…”

Resonant Inelastic Soft X-Ray Scattering at Hollow Lithium States in Solid LiCl

“…Furthermore, it is well known that fluorescence yield spectra can differ substantially from absorption spectra, especially in few-electron systems [20]. The observed splitting is, however, far from any energy splitting between ionic states which can be considered [21].…”