The electron spin resonance spectrum of CH3ĊH(CO2H) between 100°K and 200°K

Abstract
The electron spin resonance spectra of CH3ĊH(CO2H) in γ-irradiated α-alanine between 100°k and 200°k differ from the spectra obtained above and below this range. The ‘intermediate temperature’ spectra are interpreted in terms of a rather critical rate of rotation of the methyl group. From the line-width change near 100°k and 200°k an estimate of approximately 4 kcals has been made for the activation energy hindering the rotation of the methyl group.