Study of Moessbauer effect of a lattice containing a pair of point defects at high temperature limit

The double time Green's function technique has been used to calculate Moessbauer parameters at the high temperature limit for a lattice containing a vacancy and an interstial atom. Only the potential term in the perturbed part of the Hamiltonian has been considered in calculating the Debye-Waller factor and the energy shift under harmonic approximation. The result is a broadening of the Moessbauer line and an additional energy shift which, however, may not be well observed. (author)