Automatic spin-Hamiltonian diagonalization for electronic doublet coupled to anisotropic nuclear spins applied in one- and two-dimensional electron spin-echo simulations

We explore the possibility of putting together some earlier theoretical inv entions in electron paramagnetic resonance (EPR) into an efficient method l eading to accurate explicit expressions of echo modulation spectra in one a nd two dimensions. The resulting "automatic" diagonalization of the high-fi eld spin-Hamiltonian gives a quick method for Electron spin-echo modulation computations. It accounts accurately for the effects of nonaxial electron Zeeman and hyperfine coupling tensors to an arbitrary system of nuclei in a ny relative orientations, including also the secular part of the quadrupole tensors in the computation of the modulation frequencies. Explicit express ions for the time-resolved signals, involving a single geometric parameter, particularly useful in economizing powder simulations of multipulse sequen ces like hyperfine sublevel correlation spectroscopy (HYSCORE), are present ed. Finally, implementation in a complete package including fundamental EPR -line shape, primary-echo, stimulated-echo. and HYSCORE: simulations and ap plication to computations in experimentally interesting model systems is de monstrated. (C) 2000 John Wiley & Sons, Inc.