Nuclear Spin–Lattice Relaxation in Axially Symmetric Ellipsoids with Internal Motion

The calculation of the nuclear-magnetic-resonance spin–lattice relaxation time has been extended to include molecules which approximate an axially symmetric ellipsoid and have internal motion about an axis at any constant angle to the symmetry axis of the ellipsoid. The calculation is carried out explicitly for two models of internal motion. These are, random reorientation among three equivalent positions 120° apart, and rotational diffusion.