Dielectric Relaxation in Symmetric-Top Molecules at Radio Frequencies

Abstract

Dielectric relaxation has been observed in gaseous methyl fluoride (CH3F) and fluoroform (CHF3). The dispersion χ′ was measured at 30 MHz as a function of density at constant temperature (309 °K) over a density range from 10−3 to 1.0 amagat. Molecular collisions have been treated by assuming an exponentially decaying dipole-moment correlation function. The collision diameters obtained have been compared with those obtained from microwave nonresonant absorption. The relationship between information from dielectric relaxation measurements and nuclear spin–lattice relaxation measurements is discussed briefly.