Cationic double K-hole pre-edge states of CS2 and SF6

Abstract

Recent advances in X-ray instrumentation have made it possible to measure the spectra of an essentially unexplored class of electronic states associated with double inner-shell vacancies. Using the technique of single electron spectroscopy, spectra of states in CS2 and SF6 with a double hole in the K-shell and one electron exited to a normally unoccupied orbital have been obtained. The spectra are interpreted with the aid of a high-level theoretical model giving excellent agreement with the experiment. The results shed new light on the important distinction between direct and conjugate shake-up in a molecular context. In particular, systematic similarities and differences between pre-edge states near single core holes investigated in X-ray absorption spectra and the corresponding states near double core holes studied here are brought out.

Efficient calculations of a large number of highly excited states for multiconfigurational wavefunctions

“…Double‐core‐hole states are significantly less common than single‐core‐hole ones. However, they lead to an enhancement of the chemical sensitivity and have therefore gained renewed attention with the appearance of new intense X‐ray lightsources …”

KL double core hole pre-edge states of HCl

“…In particular, in the work of Püttner et al, 8 the formation of DCH states of the form 1s À1 2p À1 nc in Argon has been studied, and by applying a fit model and the Rydberg formula, the lowest ionization potential required for promoting the two core electrons into the continuum could be extrapolated. Similarly, Goldsztejn et al 9 recorded the 1s À2 V DCH states in Ne and Feifel et al 14 in CS 2 and SF 6 , where V refers to the valence orbital of the excited electron.…”

Double-core-hole states in CH3CN: Pre-edge structures and chemical-shift contributions

“…Subsequently, a theoretical model accounting for these two processes including its application for the interpretation of other experimental spectra was published by Carniato et al 15,16 demonstrating a very good agreement between experiment and theory. 4,6,8 In the present work, electron spectra associated with the formation of C 1s −2 V and N 1s −2 V DCH states of the CH 3 CN FIG. 1.…”

“…The development of third-generation synchrotron radiation (SR) sources and X-ray free electron lasers (XFELs) enabled the observation of double-core-hole (DCH) states [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] at unprecedented ease. DCH states can be formed by simultaneous or sequential excitation and/or removal of two core electrons, as originally discussed by Cederbaum et al 17 for the case of the two core electrons being ejected into the continuum.…”

“…Using the same technique as in Refs. 5 and 6, Feifel et al 8 obtained molecular ss-DCH pre-edge states of CS 2 and SF 6 involving the different 1s levels, and Koulentianos et al 9 investigated the DCH pre-edge states of HCl involving the 1s and 2p as well as the 1s and 2s inner shells akin to the Ar work of Ref. 5.…”