Two-body relationship between the Kaxiras-Pandey and the Murrell-Mottram potential functions

Abstract

A relationship between the 2-body interaction of the Kaxiras-Pandey (KP) and the Murrell-Mottram (MM) empirical potential energy functions is developed in this paper. By equating the derivatives of these two potentials up to the third order at the equilibrium bond length, parameters from both potential functions (2-body part) can be shown to be related by a scaling factor. Upon graphical examination, the discrepancy between the two potential functions' 2-body interaction reveals that the KP function is more suitable for "harder" bonds while the MM function is favorable for curve-fitting "softer" bonds. Hence, for large-distortion, the 2-body portion of the KP is suggested when the distortion is prescribed, but the 2-body part of the MM is recommended when traction is prescribed, in order to give a more pessimistic prediction for the purpose of conservative design. © 2005 The Physical Society of the Republic of China.