Quasi-harmonic analysis of the thermodynamic data for gold and an estimate of Θ^M(T)

Abstract

The moments of the Au frequency spectrum have been calculated in the usual manner from available thermodynamic data. These results are expressed in terms of the effective Debye temperatures, OD(n). Unlike many materials, the values of OD(n) for Au increase monotonically with increasing n. Values of the characteristic temperature associated with the Debye-Waller factor are determined [O~(0, V0) = 171 + 2 °K and O~(300, Vs00)= 163 +_ 1 °K], and the temperature dependence of O~V~(7", Va-) is estimated. Our results are compared with recent M6ssbauer and X-ray data. The comparison with the M6ssbauer measurements, which were performed at 4.2< T_< 100°K., yields a value of ~4.4 for the internal conversion coefficient, e, for the 77 keV, ~-ray line of Au 197, this agrees well with a recent independent determination of a=4.23 +0.09. However, our results for OM(T, VT) disagree, to within quoted estimates of error, with the results of published X-ray measurements. It is suggested that additional X-ray experiments extending to low temperatures would help to resolve these discrepancies.