Original Articles
Brijesh Kumar Pandey
Abstract
Variation of lattice parameters depends on the surface energy and the size of nanoparticles. In the present work the model developed by W.H. Qi, and M.P. Wang to predict the size and shape dependence of lattice parameters of metallic nano-particles, has been reviewed in context to the different expressions of surface energy for the nanoparticles of Cu, Au and Pt. I have derived the expression of surface energy for the nanoparticles considering of surface effect with analogy of cohesive energy of nanoparticles. I have used the expression of surface energy with the consideration of broken bonds and surface relaxation, temperature coefficient of surface free energy and the expression of size dependent surface energy derived by me to predict the variation of lattice parameters of nanoparticles. Computed results are compared with the available experimental data from which it is clear that the results obtained for the expression of surface energy derived by me are in good agreement with the experimental results. Main beauty of the suggested expression for the surface energy is that, it is very simple and based on fundamental concept of surface effect. The use of this expression in the model for the prediction of size dependence of lattice parameters reduces the requirement of input parameters therefore; the present expression of surface energy to predict the variation of lattice parameters for different metallic nanoparticles is the most suitable and consistent.