Electron spin relaxation in solutions of transition metal ions with S ≥ 1. Conditions where the Redfield limit is valid

Abstract
Electron spin relaxation for S = 2 by modulation of the quadratic zero- field splitting under conditions when Te2 > Tl, is treated theoretically. It is shown that the appropriate relaxation matrices when solved numerically yield at high-field strengths two different electron spin relaxation times with different relative weightings. The relative weights are field-dependent, there being only one longitudinal and one transverse relaxation time at low-field strengths. The relaxation matrices for S = 1, 3/2,2,5/2 are summarized in the Appendix.