MOLECULAR MOTIONS IN PURE LIQUID N2O .1. ANISOTROPIC INTERACTIONS

The Raman spectra of pure liquid nitrous oxide were measured along the co-existence curve from 293K down to the triple point at 183K. Utilizing the deconvolution technique, the reorientational line broadening of the depolarized component was separated from the broadening due to other processes, especially vibrational relaxation. Near the critical point, the experimental rotational correlation functions, φ2R(t). are weU described by the analytical expression of the independant binary collision (IBC) model. The validity of the IBC model has been investigated through the comparison of its unique correspondence parameter with the angular momentum correlation time calculated from the hard sphere model. The mean square torque, <(OV)2)> acting on the N2O molecule, in the whole density range considered, was estimated with the aid of the memory formalism. Our results for <(OV)2> were found to be in reasonable agreement with the calculations of 3rd order perturbation theory of molecular fluids proposed by Gray, Gubbins et al. The density dependence of <(OV)2> has been investigated and its negative behaviour in the high density range is attributed to the high order correlation between the molecules. © 1979 Taylor & Francis Ltd.