Understanding the uncertainty of interatomic potentials’ parameters and formalism

Abstract

A sensitivity analysis of the modified embedded atom method (MEAM) potential for bodycentered-cubic uranium and zirconium was performed in order to examine and understand the uncertainty in the parameters and formalism of the interatomic potential. The sensitivity analysis was conducted using one-at-a-time (OAT) sampling of the parameters and how they affected the ground state, thermal, and alloy structural and thermodynamic properties. The performed analysis was able to uncover the properties that can be easily varied or adjusted like the lattice constant, and the properties that had little variance like the heat capacity. The observed analysis on the ground state properties was found to correspond well with previously published results, after which the thermal and alloy properties were examined. A new method of categorizing changes in the alloy properties was developed that allows for the discrimination of bonding behaviors, determining if the strength of the bonding between atoms changed or if the manner in which they were bonded together changed.

Structure and Phase Transition Features of Monoclinic and Tetragonal Phases in U–Mo Alloys

“…Molecular dynamics (MD) simulation is a powerful tool to study physical properties of matter at the atomistic level [24][25][26]. In this work, we studied the structure of U-Mo alloys using molecular dynamics simulations with a novel interatomic potential [23].…”

Uncertainty Quantification and Reduction of Molecular Dynamics Models

“…In practice, a computationally convenient and physically motivated functional form of the potential is assumed and parameterized to match either fundamental electronic structure calculations or experimental data [1]. Only recently have systematic evaluations of these errors begun to be performed [6,7]. As one practical approach, Moore et al [7] performed a parameter sensibility study where the parameter of an interatomic potential is varied one at a time and its effects on properties (e.g., lattice constant, elastic constants, cohesive energy and enthalpy of mixing) are determined using MD simulations.…”

“…Only recently have systematic evaluations of these errors begun to be performed [6,7]. As one practical approach, Moore et al [7] performed a parameter sensibility study where the parameter of an interatomic potential is varied one at a time and its effects on properties (e.g., lattice constant, elastic constants, cohesive energy and enthalpy of mixing) are determined using MD simulations. Such a study reveals the relative importance of each of the potential parameters.…”

Modeling Salt-Material Interactions in Molten Salt Reactors: Opportunities and Path Forward

“…Molecular dynamics (MD) is an atomistic modelling method in which atomic potential energies and forces between atoms are defined by an empirically fit interatomic potential (IP) and the atomic system is evolved over a period of time according to Newton's equations of motions. When sufficient data is available to construct a quality interatomic potential, IPMD calculations have been shown to perform exceptionally well in the prediction of many material properties [11][12][13][14][15]. Calculations quickly lose accuracy, however, when potential fitting data is scarce or non-existent.…”