Perturbation solution of the spin hamiltonian of low symmetry using the projector technique

Abstract

Second-order perturbation solutions of the spin hamiltonian are presented for the case of most general symmetry conditions, when the principal axes of the different tensors may be non-collinear and the tensors g and A may be asymmetric. In order to obtain a concise formalism we introduce projectors on the quantization directions of the electron and nuclear spins, which make the determination of complete Euler transformation matrices unnecessary. The angular dependence of the intensities are discussed both for the allowed and different first-order for bidden transitions for randomly oriented samples.