Analysis of anisotropic hyperfine interaction distributions in two-dimensional four- and five-pulse electron spin echo envelope modulation spectra of protons in single crystals

The effect of the distribution of anisotropic hyperfine interaction on the cross peak line shape of protons in single crystal two-dimensional four-pulse electron spin echo envelope modulation spectra are discussed. The inclusion of an additional mixing pulse in the evolution period of the four-pulse sequence allows the simultaneous measurement of cross and sum peaks in a two-dimensional experiment. The sum peaks directly map the distribution of the anisotropic hyperfine interaction. As an experimental example the hyperfine interaction parameter distribution of protons localized in hydrogen bonds of a mixed single crystal betaine phosphate / betaine phosphite is examined. © Springer-Verlag 1997 Printed in Austria.