An investigation into low-lying electronic states of CH3S2 via threshold photoelectron imaging

Abstract

Threshold photoelectron imaging of CH3S2− was performed, providing the electronic spectroscopy information of the CH3S2 radical. This allows for the accurate determination of the electron affinity of CH3S2 (EA = 1.757 ± 0.002 eV) and the term energy of the first vibrational excited state (T0 = 1.037 ± 0.005 eV) to be directly determined from the experimental spectra. The vibrational characteristics were assigned mainly to the S–S stretching mode in the ground state (X2A″), as well as the S–S–C bending mode in the first excited state (12A′) in conjunction with Franck–Condon simulations. The photoelectron angular distributions indicate that the photodetachment process predominantly involves two different molecular orbitals of CH3S2−. In addition, angular filtering photoelectron spectra were employed to further support the assignment of the spectral bands.