Resolution Enhancement of ESR Spectra from Irradiated Single Crystals of Glycine

The electron spin resonance spectrum of +H3NĊHCOO− in single crystals of glycine γ irradiated at room temperature has been re-examined at X band and evaluated by resolution-enhancement technique. The resolution enhancement is obtained by reducing the linewidth by a factor of maximum 0.55 at the expense of the signal-to-noise ratio. The calculations, which require a high-speed digital computer, consist of three steps: (1) transformation of the experimental spectrum to a complex Fourier plane, (2) multiplication of this Fourier spectrum with a suitable linewidth-reduction function, and (3) inverse transformation back to the real plane. From the obtained constants, the hyperfine coupling tensors have been calculated, including contributions from second-order effects (ΔMI = ± 1). One of the principal values of one of the tensors was appreciably affected by these second-order effects. The results fully confirm the structure of the radical.