Determination of anisotropy of molecular motion with carbon-13 spin-lattice relaxation times

A computer program has been written to calculate the rotation diffusion tensor for anisotropic motion from ^(13)C spin-lattice relaxation-time data. Application of this program to ^(13)C spin-lattice relaxation-time measurements of methyl substituted cycloalkanes is shown. The degree of anisotropic motion within this series of compounds becomes smaller with increasing ring size. The lower limits of the barriers of rotation for the methyl groups are estimated.