Application of a new perturbation theory to evaluate the shear and bulk viscosity coefficients

Three liquids, CH₃F, CH₃Cl and CHF₃, have been submitted to systematic investigation in the microwave and far infra-red frequency domains.

The studies have been extended over a gradual variation of temperature and density scanning the whole liquid range beneath the critical region. Accordingly, the relative location in time of absorption processes were observed to evolve towards each other as the liquids expand when approaching their critical region.

We discuss the dielectric relaxation processes and their characteristic times, together with some very important features from the very intense absorption in the far infra-red. The correlative dispersion is fitted by a distribution of resonances model. The occurrence of specific alignment effects are shown to be responsible for local enhancement of the dipole moments, resulting in excess of integrated intensities.

Throughout this report a direct presentation of the experimental features displays already a number of characteristics of molecular dynamics. Their analysis will be completed and refined through the correlation functions formalism developed in a following paper.