LINE SHAPES FOR PARAMAGNETIC IONS IN SOLUTION

Abstract

The paramagnetic resonance absorption curve, for transition metal ions in solution frequently grows narrower as the temperature of the solution is raised. This has been attributed by various authors to rotational narrowing due to the motion of the paramagnetic ion and its strongly associated nearest, neighbors. We present, a method for calculating tile resonance line shape itself foe such strongly interacting systems. The method involves averaging the angular dependence of each component of the line, with the average taken over the time of passage of the incident photon. The parameters appearing in the expression for the spectral density arc the line width for the gaseous ion (or the ion in a single oriented crystal), the magnetic crystal field splitting parameter and the rotational diffusion coefficient of the tumbling species. The treatment is applied to the case of the $^{6}S$ ions $Fe^{-}$ and $Mn^{++}$