Volume changes during melting and heating of zinc and cadmium tellurides

The method of penetrating gamma -radiation is used to investigate the tempe rature dependence of the density of condensed phases of zinc and cadmium te llurides in the vicinity of the melting point and to determine volume chang es during transition from the solid to liquid state. The density of zinc te lluride in the liquid phase is investigated for the first time. It is demon strated that, during melting, the density of both investigated compounds de creases and continues to decrease linear ly on heating ill the liquid state . It is noted that, in accordance with Repel's classification, zinc and cad mium tellurides melt down by the semiconductor-semiconductor pattern. The v olume changes of the investigated compounds during melting are analyzed usi ng the Clausius-Clapeyron equation. The pressure coefficients of the meltin g temperature of these compounds are estimated. and it is noted that they a le positive (dT/dp > 0). The thermal expansion of zinc and cadmium tellurid es in the solid and liquid phases is analyzed: the equation of Sirota is us ed to calculate the characteristic Debye temperatures from which the mean-s quare dynamic displacements of atoms from the equilibrium position in the s tructure of condensed phases are determined at the melting point of the inv estigated compounds.