Multielectron excitations in x-ray absorption spectra of Rb and Kr

Abstract

In the K-edge x-ray absorption of rubidium vapour and gaseous krypton, comprehensive spectra of collective excitations down to the relative probability of 5 × 10 −5 are extracted. After removal of the asymptotic Victoreen trend, the region ∼100 eV above the edge exhibits a steep decrease of the absorption coefficient attributed to core relaxation and post-collision interaction in the Auger decay. With an exponential model for the decrease,the entire spectrum of multielectron excitations is recognized as a succession of consecutive resonant, shake-up and shake-off channels. They can be identified as coexcitations of electrons from successively deeper subshells, from 5s down to 3s. The identification of excited states is aided by a quantitative modelling of subshell contributions and by natural-width deconvolution. The valence and subvalence coexcitations are shown to follow the pattern of the lighter homologues potassium and argon.

X-ray absorption in atomic potassium

“…A steeper slope immediately above the edge, attributed to core relaxation and post-collision interaction (Fig. 3) can be, in the lack of a definite theoretical expression, approximately described by an exponential decay [5]. With this model (inset of Fig.…”

“…For most other elements, however, the required density of the free-atoms is very difficult to prepare and maintain. High-temperature cells have been employed for the purpose for volatile metals [3][4][5][6][7][8][9]. The range of application of the cells depends critically on the material for the windows: it must withstand the elevated temperature, the pressure difference and the chemically aggressive vapor, at a minimum attenuation of the X-ray beam.…”

High-resolution x-ray-emission study of1s4pand1s3dtwo-electron photoexcitations in Kr

“…Noble gases, which are easy to manipulate experimentally and are also easier to handle theoretically, are particularly suited for absorption studies of multielectron excitations. Relatively strong multielectron spectral features have been identified in the measured high-resolution Kand L-edge x-ray-absorption spectra of several noble gases [2,[8][9][10][11][12][13][14][15].…”

“…Multielectron photoexcitations in krypton were studied extensively using x-ray-absorption spectroscopy [11][12][13][14][15]. Schaphorst et al [13] provided absolute photoabsorption cross sections for [1snp,nd] excitations.…”

“…A detailed theoretical analysis of the measured multielectron spectral features was performed. Later, a natural-linewidth deconvolution technique was applied to the experimental spectra, which were recorded with improved resolution and sensitivity by Kodre et al [14] to reach a clear identification of the multielectron spectral features. Despite using extensive theoretical modeling and the most advanced deconvolution analysis the above-mentioned absorption studies still face the inherent problem of the underlying dominant single-electron photoionization component.…”