VIBRATIONAL AND ROTATIONAL RELAXATION OF CYCLOHEXANE IN THE PURE STATE AND IN SOLUTION

Correlation functions φ(t) and correlation times for the v 22(Eg) band of C6H12 in the pure liquid, in liquid solutions in CCl4, CHCl3, CH 3I, and CS2 and in some of the corresponding solid phases have been obtained from spontaneous Raman scattering. Reorientational correlation times of C6D12 in these media were obtained from 2D spin relaxation measurements. Measurements of the relative intensities of the site group components of v22 in solid phase II of C6H12 and of the second moment of v22 in neat C6H12 liquid showed the dominance of the βxx-βyy, βxy contribution to this Raman band. The reorientational contributions to φ(t) were estimated from the reorientational correlation times of C6D12 by assuming the applicability of the J-diffusion model and the equality of the angular momentum correlation times for C6D12 and C 6H12. The vibrational correlation functions obtained showed a slight increase in vibrational relaxation rate with increasing temperature, the absence of large differences in vibrational relaxation in liquid and plastic solid phases, and a decrease in vibrational relaxation rate when C6H12 is dissolved in polar and nonpolar solvents. Variations in the reorientational correlation time of C6H 12 with solvent and temperature are interpreted in terms of the anisotropy of the intermolecular potential and the solution viscosities. © 1979 American Institute of Physics.