GRUENEISEN PARAMETER
Definition
A <GRUENEISEN PARAMETER> is a <Property> that describes the effect that changing the volume of a crystal lattice has on its vibrational properties, and, as a consequence, the effect that changing temperature has on the size or dynamics of the lattice. The term is usually reserved to describe the single thermodynamic property γ, which is a weighted average of the many separate parameters γi entering the original Grüneisen's formulation in terms of the phonon nonlinearities. It is calculated as gamma = alpha/(kappa.c.rho) where alpha is the cubic expansion coefficient, kappa is the isothermal compressibility, c is the mass heat capacity at constant volume and rho is the volumetric mass