To resolve transitional entropies and thermophysical contributions to the heat capacity extending over relatively large ranges of temperature, we have developed two rather specialized methods for the evaluation of the (vibrational) lattice heat capacity valid to a high degree of accuracy compared to the typical extant procedures. The earlier developed method is designated the "Volume Priority Method," and it takes into account the relative predominance of volume (rather than mass) over the "chemical thermodynamic region" below 300 K. It has been employed in recent years in the resolution of Schottky contributions arising from the splitting of the ground state by the crystalline electric fields of lanthanide salts with excellent results. The newer method is the "Komada/Westrum Phonon Density Distribution" method and although it has a generic resemblance to the well-known Debye approach it succeeds where Debye fails. It has been used for the resolution of magnetic and other transitions in such mineral systems as deerite and grunerite and enables the resolution even of minute electron delocalization phenomena. Finally, taking advantage of recent developments in the closely related Barber-Martin approach in the analysis of heat capacities, we extend the treatment to alkali silicates-both vitreous and crystalline. Meaningful values are provided for several fundamental physical parameters which correlated with other elastic and thermal properties by (in contrast to Debye theory) taking the dispersion and the resolution of acoustic and optic modes into account. Differences in the primitive volume between vitreous and crystal phases are noted and the extension of the Komada/Westrum treatment to vitreous phases enabled.
