Effective Modulus of Elasticity and Grüneisen Parameter of Chalcogenide Glasses in the As–Tl–S System

Abstract

The product of the density of a solid with the square of the root mean square velocity of deformation waves in it, which has features characteristic of elastic moduli, is named an effective modulus of elasticity. We demonstrate that the ratio of the bulk modulus to the effective modulus of elasticity of oxygen-free chalcogenide glasses is a single-valued function of Poisson’s ratio, like in the case of oxide glasses. The effective modulus of elasticity is closely related to the Grüneisen parameter, which quantifies anharmonicity. Based on the single-valued relation between the Grüneisen parameter and Poisson’s ratio, we discuss the nature of the interrelationship between harmonic (linear) and anharmonic (nonlinear) quantities.