Kinetic Theory–Memory Equation Approach to Nuclear Magnetic Relaxation in Molecular Gases. I. General Formulation for Homonuclear Diatomics

Abstract

By considering nuclear magnetic relaxation in gases of homonuclear diatomic molecules from the point of view of kinetic theory and then applying the Zwanzig projection operator technique to the relevant kinetic equation, correlation function formulas are obtained for the longitudinal and transverse relaxation times T1 and T2 and for the intermolecular contribution to the chemical shift σ. The role of the transformation to a frame of reference rotating at the nuclear Larmor frequency is clarified and the various approximations inherent in both the usual correlation function and kinetic theory descriptions are carefully pointed out. Dispersion relations existing between T2−1 and σ when expressed as functions of the magnetic field strength are obtained and the conditions under which they may be expected to hold are discussed.