Structural Order and Vibrational Relaxation of Phenylacetylene in Benzene in Liquid Solutions and Frozen Matrices at Low Temperatures. Raman Spectra of Phenylacetylene in Benzene at 77 K

Raman spectra of the νS(C⋮C) stretching mode of phenylacetylene (PA) dissolved in benzene have been recorded in liquid solutions at room temperature and in solid-state frozen matrixes at 77 K as a function of concentration. The spectra at low temperature reveal spectacular changes in comparison with those observed in liquid solutions. The results given in this paper illustrate the change of the mechanisms of vibrational relaxation due to structural reorganization around the molecular oscillator due to different molecular environments.