Orientation Dependence of the Electron Spin Resonance Spectrum of Di-t-butyl Nitroxide

Abstract

Comparisons of theoretical calculations and experimental results are reported for the anisotropy of the hyperfine splitting and g value of the di‐t‐butyl nitroxide free radical. Extensive experimental data were collected with a microwave frequency of 9.5 GHz with supplementary data collected at 35 GHz. Several approximations to the Hamiltonian are discussed and compared to the results of the exact solution. Explicit equations for several approximations are given in terms of the principal values of the splitting and g‐value tensors and the orientation of the nitroxide in the external magnetic field. The more accurate approximations should prove useful in the interpretation of nitroxide ESR spectra by decreasing the programming difficulties and the time requirements involved in computer simulation of nitroxide spectra.