Lattice dynamics,third order elastic constants and thermal expansion of gadolinium

A systematic investigation of the lattice dynamics, second and third order elastic constants and the temperature variation of the effective Grüneisen functions has been carried out in gadolinium using Keating's approach. The ten third order elastic constants are calculated using five anharmonic parameters. The present model reproduces the measured pressure derivatives of the second order elastic constants of gadolinium well. The low and high temperature limits gg_L and gg_H of the lattice thermal expansion are evaluated. The agreement between the calculated gg_H and that obtained from the thermal expansion and specific heat data of gadolinium is good.