Nuclear spin–lattice relaxation of methyl groups via multiphonon processes
Journal
The Journal of Chemical Physics
Journal Volume
94
Journal Issue
3
Pages
2077--2083
Date Issued
1991-02
Author(s)
Robert Silbey
Abstract
The empirical correlation between the logarithm of tunneling splittings and the temperature at which the spin–lattice relaxation time is minimum for methyl groups in different molecular crystals is explained successfully by taking multiphonon processes into account. We show that one-phonon transitions dominate in the low barrier limit. However, in the intemediate barrier range and high barrier limit, it is necessary to include multiphonon processes. We also show that the empirical correlation depends only logarithmically on the details of the phonon bath.
Type
journal article