MAGRES: a general program for electron spin resonance, ENDOR and ESEEM

Abstract

The program package MAGRES (MAGnetic RESonance) is able to calculate e.s.r., ENDOR (without relaxation) and ESEEM spectra for, in principle, any spin system in single crystals as well as in powders. The spin Hamiltonian may be constructed from electron and/or nuclear Zeeman interactions, exchange and hyperfine couplings, zero-field splittings and nuclear quadrupole interactions. For the calculation of eigenvalues and eigenvectors the program uses exact diagonalization, hence no assumptions have to be made about the relative magnitude of the various interactions. Comparison of the calculated with the experimental frequencies of single-crystal spectra permits the optimization of the interaction tensors. The computed tensors may be checked by comparison of the experimental and the calculated intensities of single-crystal and powder spectra. Simulation of ESEEM spectra is possible for the two- and three-pulse sequence, and the effect of the dead-time may be included. The program can also be used for the calculation of c.w. n.m.r. spectra.