Abstract:
Time correlation functions (TCF) of one-dimensional rotational brownian motion
of classical top in $n$-multiple periodic potential are investigated on the basis of the
solution of the modified equation of rotational diffusion which takes into account
approximately the inertial effects. Explicit expressions for TCF are obtained in the
limiting cases of large and small barriers. It is shown that the model of free rotational
diffusion is valid when the value of the ratio of the barrier height to mean heat energy
is less than one, while the hopping model is valid when this value is larger than three.
Connection between the correlation time, the height of the rotation barrier and the
friction coefficient characterizing influence of the medium is obtained. The results
obtained are applied to the problem of calculating the TCF for translational motion
of admixture atom in a crystal and to some other problems.