An Investigation of the Alkali Metals in the fcc Structure Using an Embedded-Atom-Method (EAM) Model

Embedded-atom-method models have been used in the calculation and prediction of many vibrational and thermal properties of materials. In 2012 Wilson and Riffe constructed a model that predicts dispersion relations and frequency-moment Debye temperatures of the alkali metals with a greater degree of accuracy than previous models. The Wilson-Riffe model was implemented using MATLAB code. Here that model is extended to model alkali metals in the close-packed fcc structure. Code development is discussed, and results are presented for dispersion relations, density of states, Debye temperatures and free energy. The vibrational free energy combined with a suitable constant representing the electronic free energy of these metals is found to be the driving factor in the phase transition to close-packed structures that occurs in Lithium and Sodium at low temperatures