Anharmonic Study on the Debye‐Waller Factor for a Vacancy‐Trapped Mössbauer Impurity in Solid Solution of Aluminium

Abstract

AbstractThe effect of anharmonicity on the Debye‐Waller factor for a simple cubic lattice containing Mössbauer atoms as impurity along with vacancies at the lattice points is evaluated theoretically using the double‐time Green's function technique in the high‐temperature limit. The contributions of the anharmonic lattice vibrations to the Debye‐Waller factor for 57Fe atoms present as a dilute impurity in solid solution of aluminium are also estimated. The exponent of the Debye‐Waller factor is found to increase much more rapidly at higher temperature for a defect lattice than that for a perfect lattice due to the presence of the anharmonic terms in the expansion of the potential energy of the crystal.