Tunneling of CH₃ Groups in Molecular Crystals of the X(CH₃) _n Type

Abstract

A system of coupled CH₃-type torsional oscillators embedded in a crystal field of definite symmetry and interacting with an externally applied d.c. magnetic field is considered. Interaction among the neighboring CH₃ groups is assumed to be the result of electrostatic interaction of the respective charge distributions. To obtain an approximate but nevertheless reasonably accurate description of the lowest lying energy eigenstates we examine the minima of the potential energy of the system. Next we construct Gaussian wave packets peaked at each of these minima and form linear superpositions in order to respect the symmetries of the problem under consideration.