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

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.