Flesch R, Serdaroglu E, Brykalova XO, Kan EI, Klyushina ES, Krivosenko YS, Pavlychev AA, Rühl E. Gas-to-cluster effects in S 2p-excited SF(6).
J Chem Phys 2013;
138:144302. [PMID:
24981530 DOI:
10.1063/1.4798975]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High resolution X-ray spectroscopic studies on free SF6 molecules and SF6 clusters near the S 2p ionization thresholds are reported. Spectral changes occurring in clusters for the intense molecular-like S 2p1/2,3/2 → 6a1g-, 2t2g-, and 4eg-resonances are examined in detail. Neither gas-to-cluster spectral shifts nor changes in peak shape are observed for the pre-edge 6a1g-band. Significant changes in band shape and distinct gas-to-cluster shifts occur in the S 2p1/2,3/2 → 2t2g- and 4eg-transitions. These are found in the S 2p-ionization continua. The quasiatomic approach is used to assign the experimental results. It is shown that a convolution of asymmetric and symmetric contributions from Lorentzian and Gaussian line shapes allows us to model the spectral distribution of oscillator strength for the S 2p1/2,3/2 → 2t2g-, and 4eg-transitions. The asymmetry is due to trapping of the photoelectron within the finite size potential barrier. The Lorentzian contribution is found to be dominating in the line shape of the S 2p → 2t2g- and 4eg-bands. The spectroscopic parameters of the spin-orbit components of both the 2t2g- and 4eg-bands are extracted and their gas-to-cluster changes are analyzed. The photoelectron trapping times in free and clustered SF6 molecules are determined. Specifically, it is shown that spectral changes in clusters reflected in core-to-valence-transitions are due to a superposition of the singly scattered photoelectron waves at the neighboring molecules with the primary and multiply scattered waves within the molecular cage.
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