Sensitivity of the continuous-wave saturation of conventional EPR spectra to slow rotational motion

Abstract

A simple analytical treatment is presented for the sensitivity of the power saturation of conventional spin label EPR spectra to slow rotational diffusion in the sub-millisecond range. Phenomenologically, this describes published data on spin-labelled haemoglobin very well and yields an easily applicable calibration of the spectral dependence on rotational correlation time.