The structural configurations of Ethylene Trithiocarbonate in the binary mixture (SCS 2 CH 2 CH 2 +CHCl 3 ) investigated by polarized Raman: Experimental and quantum chemical results

The isotropic and anisotropic components of the Raman spectra of CS stretching in Ethylene Trithiocarbonate (SCS2CH2CH2, ET) shows noncoincidence effect (NCE). The calculated absolute Raman cross-section (ARCS) of CS stretching initially increases with the dilution of concentration to a maximum and then decreases. This unusual behavior indicates the existence of self-association. Thus we proposed aggregated model and the dimer structure were optimized with DFT/PCM to explain the NCE and ARCS behaviors. Vibrational spectra and depolarization-ratio were calculated for monomer and dimer individually, the dimer is in good accordance with the experimental data. The strong antiparallel CS vibrational coupling in neighboring molecules accounts for the frequency shifts of the CS stretching.