Sulfur 1 s excitation of S_2 and S_8: Core-valence-and valence-valence-exchange interaction and geometry-specific transitions

摘要

Sulfur 1 s excitation of S_2 and S_8 is reported. The experments made use of monochromatic synchrotron radiation from the BW-1 beam line at the HASYLAB (Hamburg, Germany), where total cation yields and photoionization mass spectra were investigated as a function of the source temperature that was used for evaporation of #alpha#-sulfur. The near-edge structure undergoes characteristic changes as a function of the source temperature, reflecting significant size-and geometry-dependent changes in electronic structure of the sulfur clusters. The detailed analysis of the near-edge feature is obtained from ab initio (MR-SDCI) calculations that focus on S_8 and S_2. The present results are discussed in comparison to previous work on inner-shell excited sulfur clusters as well as condensed sulfur. The near-edge structure of S_2 is compared to that of O_2 and Se_2, yielding characteristic differences in core-valence and valence-valence-exchange interaction.