Dielectric and Pressure Virial Coefficients of Imperfect Gases. V. Octopole Moments of CH4 and CF4

Abstract

Dielectric second virial coefficients varying inversely with temperature have been determined by cyclic expansion measurements at 6.6, 49, and 100°C in the pressure range 1–100 atm. Attributing the temperature dependent contribution to dipole moments induced in one molecule by the octopole moment of a second gives 3.0× 10−34 and 4.4× 10−34 esu for the molecular octopole moments of CH4 and CF4.