Analytical expression for the energy distribution of Mossbauer transitionsin the presence of mixed interactions

Based on the analytical results for intensity tensor components, expression s for energy distribution of Mossbauer 3/2-1/2 transitions in the case of a uniform magnetic field and randomly oriented electric field gradient (EFG) are presented. The expression obtained contains elliptic integrals. The lo garithmic singularities appearing in the integrals are integrable and their origin is discussed. Next, the shape of the Fe-57 Mossbauer spectrum in st andard, as well as recently developed, circularly-polarized Mossbauer spect roscopy was derived. The general results obtained agree with previous works in the limiting cases, e.g., with the analytical shape obtained for asymme try parameter set to zero, and the results obtained by perturbation methods . In the limit of local axial symmetry of the EFG (eta = 0), expressions si mplify to an algebraic form and the singularities are of (x - x(0))(-1/2) t ype. (C) 2000 Elsevier Science B.V. All rights reserved.