Excited-state structural dynamics and vibronic coupling of 1,3-dithiole-2-thione - resonance Raman spectroscopy and density functional theory calculation study

摘要

1,3-Dithiole-2-thione (DTT) was synthesized and haracterized using NMR, FT-Raman, FT-IR, UV spectroscopies. Resonance Raman spectra (RRs) were obtained with 341.5, 354.7 and 368.9 nm excitation wavelengths and density functional calculations were done to elucidate the electronic transitions and the RRs of DTT in cyclohexane solution. The RRs indicate that the Franck-Condon region photodynamics is predominantly along the C=S stretch+ H-C=C-H scissor v_4, accompanied by the H-C=C-H scissor v_3, S-C-S symmetric stretch v_6, C=C stretch v_2, and overtone of the non-totally symmetric S=C-S2 out-of-plane deformation 2v_(11). The excited-state dynamics and the force constant of C=S stretch calculated by the RRs were discussed.