Melting and thermodynamic properties of rare gas nanocrystals

Abstract

A self-consistent statistical method [Phys. Rev. B66, 054302 (2002)] is used to describe thermodynamic properties of free rare gas nanocrystals using thin plates as examples. It is shown that size influence on thermodynamic properties of nanocrystals is caused by size-dependent quantization of the vibration spectrum affecting the parameters of a statistical distribution function of atomic displacements and, thus, governing size dependence of average values of energetic contributions to the Gibbs free energy of the system. For Xe nanocrystals, we present calculated size dependences of the Debye temperature, heat capacity, interatomic distance, melting temperature, etc. PACS: 64.70.D-Solid-liquid transitions;65.80.+n Thermal properties of small particles, nanocrystals, and nanotubes.

Heat release in clusterization of nanoparticles

“…A dramatic increase in C P corresponds to the premelting temperature range, in accord with results of calorimetric studies of nanocrystalline materials 2,3 . A similar behavior of C P (h) was also theoretically found for the rare-gas nanocrystals 13 . As crystal size decreases, the premelting anomaly takes place at lower temperatures.…”

“…Similar sizedependent melting curves are inherent to all kinds of freestanding nanocrystals, e.g. rare-gas nanocrystals 13 , thus implying universality of the mechanism of size-dependent quantization of vibrational spectra which is responsible for a shift of temperature dependence of thermodynamical properties of nanocrystals.…”

Van der Waals Clusters

“…A statistical mechanics model for the melting of Xe nanocrystals, much larger, in fact, than the small clusters just discussed, reveals an appreciable lowering of the melting temperature, as the size of the nanocrystal decreases, with respect to its limiting bulk value [30]. This is a general property of clusters and nanocrystals that will be considered again in Chapter 6.…”

“…3.5). A second, sharp peak, emerges for Ar 30 , and its magnitude increases as the first peak gradually disappears. The two peaks coexist up to Ar 36 (see the case of Ar 33 in Fig.…”

Изучение Свойств Сплава Золото-Железо В Макро- И Нанокристаллических Состояниях В Различных P-T-Условиях

“…Если размерная зависимость температуры Дебая, коэффициента теплового расширения, теплоемкости и межатомного расстояния при P = 0 хорошо изучена [30] и споров не вызывает, то размерная зависимость для модуля упругости различных веществ крайне противоречива.…”