Thermodynamic Models for the Size-dependent Melting of Nanoparticles: Different Hypotheses

Gopal      Krishna Goswami; Karuna      Kar Nanda

Abstract

A careful comparison of the experimental results reported in the literature reveals different variations of the melting temperature even for the same materials. Though there are different theoretical models, thermodynamic model has been extensively used to understand different variations of size-dependent melting of nanoparticles. There are different hypotheses such as homogeneous melting (HMH), liquid nucleation and growth (LNG) and liquid skin melting (LSM) to resolve different variations of melting temperature as reported in the literature. HMH and LNG account for the linear variation where as LSM is applied to understand the nonlinear behaviour in the plot of melting temperature against reciprocal of particle size. However, a bird’s eye view reveals that either HMH or LSM has been extensively used by experimentalists. It has also been observed that not a single hypothesis can explain the size-dependent melting in the complete range. Therefore we describe an approach which can predict the plausible hypothesis for a given data set of the size-dependent melting temperature. A variety of data have been analyzed to ascertain the hypothesis and to test the approach.

Keywords: Phase transitions in clusters, 36.40.Ei, Binding energies and masses, 21.10.Dr, Thermodynamic properties of surfaces and interfaces, 05.70. Np, Melting, 64.70.dj, Surface tension, 68.03.Cd, Nanoparticles thermal properties of, 65.80.-g, 82.60.Qr, Phase transition soldliquid, 64.70.D-, Surface energy of solid surfaces, 68.35.Md