DFT-Based Optimization of Morse Potential Parameters for Selected Metallic and Non-Metallic Materials

Abstract

The accurate description of interatomic interactions is essential for understanding the structural, mechanical, and thermal properties of metals at the atomic scale. The Morse potential is a widely used empirical model due to its simple analytical form and ability to capture basic bonding characteristics. However, its accuracy strongly depends on the choice of potential parameters, which are often obtained from experimental data or semi-empirical approaches and may not reliably represent non-ideal conditions such as defects, high stress, or phase transitions. In this work, we develop, optimize, and validate Morse potential parameters for several materials, including C, B, Ti, Al, Ni, and Fe, using reference data from DFT calculations. DFT simulations are performed using the open-source Quantum ESPRESSO package to obtain total energy data for isolated atomic pairs at various interatomic separation distances. The Morse potential parameters, namely the potential well depth (D), equilibrium distance (rₑ), and stiffness parameter (α), are determined by fitting the DFT total energy curves over a wide range of interatomic distances, including regions below and above the equilibrium separation up to the asymptotic limit. The fitted parameters are validated by comparing the resulting Morse potential energy profiles with the corresponding DFT reference data. This approach ensures that the optimized parameters accurately reproduce the underlying ab initio energy landscape while retaining the computational efficiency of empirical potentials. The resulting Morse parameters are intended for use in large-scale molecular dynamics simulations, particularly for modeling ballistic impact and armor systems involving materials such as B₄C, Ti-based alloys, and polymer–metal composites. This study provides a systematic framework for deriving DFT-consistent Morse potential parameters, enabling more reliable atomistic simulations of metallic and composite materials under extreme loading conditions.