The heat capacity of gold from 300 to 1200 °K: Experimental data and analysis of contributions

Using adiabatic calorimetry the heat capacity of high purity gold has been measured from 300 to 1200 °K with an estimated accuracy of ± 1%. The experimental heat capacity at constant pressure was converted to that at constant volume using experimental data of molar volume, volume expansivity, and isothermal compressibility reported in the literature. A theoretical, or base, heat capacity at constant volume was obtained by using the Debye heat capacity, to which was added an electronic heat capacity and a contribution from the formation of equilibrium lattice defects. However, the correction for the formation of lattice defects was negligible at 1200 °K. The difference between the heat capacity obtained from the experimental data and the base heat capacity was positive, being about 2% of the heat capacity at 1200 °K. This exceess heat capacity is attributed to anharmonic lattice vibrations, but within the uncertainties in the experimental data and in the parameters used to calculate the base heat capacity, it could vanish or be slightly negative.