Use of Computer Programs in the Interpretation of Electron Paramagnetic Resonance Spectra of Dilute Radicals in Amorphous Solid Samples. I. High-Field Treatment. X-Band Spectra of π-Electron Unconjugated Hydrocarbon Radicals

The successive stages of the calculation of a high‐field electron paramagnetic resonance line shape for a radical dilute in a polycrystalline or glassy sample from the parameters of its spin Hamiltonian have been fitted into a computer program. We have considered the general case where there may be a $\frac{3}{2}$ tensor, anisotropic hyperfine couplings, and satellite lines arising from nuclei of any spin up to $\frac{3}{2}$ and approximated the component line shape by a Gaussian function of constant width. Possible uses of such a program are: (1) determining the line shapes associated with some model radicals and establishing approximate rules to facilitate the interpretation of experimental spectra; (2) checking the validity of an assignment of tensors made on the basis of some plausible structure for a species under investigation; and (3) finding the parameters which make the best fit to an observed spectrum. Applications to some π‐electron hydrocarbon radicals are presented, and the possibilities offered by such calculations are evaluated.