Analysis of slow molecular motions from nitroxyl-radical 2-mm ESR spectra (Isotropic rotators)

Theoretical spectra are examined for the 2-mm ESR range for nitroxyl radicals; these have been derived from a stochastic Liouville equation for two models for isotropic rotations (brownian and step diffusion). The broadening and shift have been examined for the high-field z component in relation to the model and to the magnetic and dynamic parameters for lorentzian and nonlorentzian line shapes. A simple method is proposed for defining the model for the rotational motion from the width and shift in this component. A universal method has been devised for evaluating the correlation times for isotropic rotations from the theoretical dependence of the broadening and shift of the high-field z component on in the range of slow movements, 2·10^–8 < < 10^–5 sec.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 1, pp. 46–53, January–February, 1987.