Specific heat related to details of the vibrational modes for a 2D nanocrystalline material

“What – if” analyses of the interfacial component of nanocrystalline materials (NCM), especially at higher temperatures, were performed using a two-dimensional model. What influence would thermal excitations have on the pair distribution function, the vibrational spectra and the specific heat, over the temperature range of 30–1200 K, if the NCM would be stable over this temperature range, i.e. if grain growth cannot occur? It turned out that reduction of the grain size and increase in temperature influenced the pair distribution function, the vibrational spectra and specific heats in a similar manner. The changes in the vibrational spectra and the specific heat with decreasing grain size or increasing temperature could be related to changes in the occupation of the vibrational modes. The so-called participation ratio (PR) proved to be a suitable means of measuring the occupation of the modes and to classify the spectra. The differences in the specific heat could be largely attributed to parts of a subspectrum, filtered out from the complete vibrational spectrum by collecting the modes of a certain participation ratio range.