INFLUENCE OF INTER-MOLECULAR INTERACTIONS ON THE KERR EFFECT IN GASES .2. EXPERIMENTAL RESULTS FOR SPHERICAL TOP MOLECULES

The Kerr effect has been measured over ranges of temperature and pressure for gaseous argon, krypton, xenon, methane, tetrafluoromethane, 2,2-dimethylpropane and sulphur hexafluoride. Measurements have been analysed in terms of a virial expansion for the molar Kerr constant, and values are reported for the first and second Kerr virial coefficients (Ak and Bk)- Tentative results for the third Kerr virial coefficient (Ck) have also been obtained for methane, tetrafluoromethane, 2,2-dimethylpropane and sulphur hexafluoride.The temperature independent Ak is directly proportional to the second electric dipole hyperpolarizability, while Bk and Ck depend on the polariza-bility of interacting pairs and triplets of molecules. Our measurements of Bk are compared with those calculated from the DID model (see preceding paper [4]), and a correlation between the ratio BKexptABKDID and molecular interaction parameters is demonstrated. The results are also compared with measurements of depolarized light scattering in compressed gases. © 1979 Taylor & Francis Group, LLC.