Paramagnetic Mössbauer relaxation spectra by simple ab initio and stochastic models

The stochastic and ab initio (resolvent) methods for the calculation of Mossbauer relaxation spectra are shortly reviewed. The relaxation matrix based on a first order dynamical Hamiltonian is calculated and corresponding simulations are presented. The spin-phonon interaction spectral bath densities are calculated in the Debye approximation for the direct one and two phonon processes. Some least squares fits are presented.