Molecular theory of brownian motion of a rigid rotor

Abstract

The molecular theory of brownian motion by Mazur and Oppenheim is extended to a rigid rotor. The exact equation of motion is derived. Expansions in powers of λ = (m/M) 1 2 are performed and the Langevin equation is obtained. The analysis is rigorous under the assumption that the correlation time of bath variables in the presence of the fixed rigid rotor is short. © 1971.