Disorder and order in long-wave high-temperature acoustics (II): monatomic liquids

Manifestations of order in topologically disordered media are analyzed. Amorphous materials and monatomic melts are considered as examples of disordered media. It is shown that in the case of close-packed liquids geometric and chemical short-range order are most clearly manifested in the acoustic properties. In these materials ordering is of a dynamical character. The temperature dependence of the acoustic properties correlates well with the results of x-ray and neutron diffraction methods of investigation and substantially supplements the latter. The contributions from loss of long-range order and intensification of thermal translational motion on melting are distinguished from one another by comparing the bulk moduli of elasticity of melts, crystals, and amorphous substances.