Theory of line width alternation in certain electron resonance spectra

Abstract

Line width alternation has been observed in the electron resonance spectrum of the durosemiquinone cation and is attributed to rotational isomerism. In this paper the situation is investigated theoretically and a method based on the Bloch equations is used to derive the shape of the spectrum for different rates of isomerization. Line width alternation arises because the total hyperfine splitting of each isomer is the same.