Analysis of nuclear quadrupole interaction effects in electron spin-echo modulation spectra by second-order perturbation methods

Abstract
The incorporation of nuclear quadrupole interaction into electron spin-echo modulation spectra by second-order perturbation methods has been developed for both two-pulse and three-pulse echo sequences. The results have been compared with exact numerical diagonalization of the Hamiltonian and with a first-order perturbation treatment. Model calculations have been carried out for deuterium (I=1) and aluminum (I=5/2) nuclei. It is shown that the second-order expressions can be used to obtain relatively accurate values for the number and distance of interacting nuclei at electron–nuclear distances greater than 0.26 nm. The procedure is more limited when the quadrupolar interaction exceeds the dipolar interaction when neither can be neglected.