Chandan Gupta, Kailash and Jitendra Kumar
For the deformed face centered cubic crystal one can get the Taylor’s series expansion of elastic energy density starting from nearest neighbor distance and hardness parameter utilizing Coulomb and Born Mayer potentials. The knowledge of the higher order elastic constants for a crystal can be used to obtain the anharmonic properties of the crystals by theoretical approach. The Lanthanum Sulphide crystal possesses face centered cubic crystal structure. The theory is developed for obtaining second, third and fourth order elastic constants of Lanthanum Sulphide single crystals up to an elevated temperature and higher order elastic constants of Lanthanum Sulphide single crystals at an elevated temperature are evaluated. The data thus obtained is used to evaluate the first order pressure derivatives of second and third orders elastic constants, second order pressure derivatives of second order elastic constants and partial contractions.
Keywords: Higher order elastic constants, Hardness parameter, Anharmonic Properties.