Inner shell excitation of thiophene and thiolane: Gas, solid, and monolayer states

The electron energy loss spectra of gaseous thiophene and thiolane in the regions of S 2p, S 2s, and C 1s are presented along with the x-ray photoelectron yield (NEXAFS) spectra of both gases in the region of S 1s excitation. The thiophene spectra are compared to the corresponding NEXAFS spectra of solid (multilayer) and monolayer thiophene on Pt (111). MS-Xα calculations of the C 1s, S 2p, and S 1s excitation spectra of free thiophene are also reported. Intercomparison of the gas, surface, and calculated spectra allows a complete interpretation of the spectral features and facilitates determination of the molecular orientation of thiophene with respect to the surface in both the compressed [thiophene on Pt (111) at 150 K] and relaxed [thiophene on Pt (111) at 180 K] monolayer phases.