Site-specific fragmentation in condensed (CH3S)2 by sulfur K -edge photoexcitation

The site-specific fragmentation by core-to-valence resonant photoexcitation has been investigated for condensed (CH3S)2 (dimethyl disulfide). The data presented are the desorption yields of the fragment ions from multilayered (CH3S)2 around the sulfur K-edge photoexcitation as well as the x-ray absorption and Auger decay spectra. The x-ray absorption spectrum exhibits the double structure of the S 1s→σ* resonance peak corresponding to the S 1s→σ*(S–S) and S 1s→σ*(S–C) photoexcitations. It was found that the S 1s→σ*(S–C) excitation is predominantly followed by the CH+3 desorption, but the CH+3 and S+ ions are desorbed in comparable intensity at the S 1s→σ*(S–S) excitation. The Auger decay spectra around the S 1s→σ* excitation revealed that there exist two kinds of sulfur KL2,3L2,3 spectator Auger decay originating from the S 1s→σ*(S–S) and S 1s→σ*(S–C) resonant excitations. The observed site-specific fragmentation is interpreted in terms of the localization of the spectator electron in each antibonding orbital, i.e., σ*(S–S) and σ*(S–C).