Understanding the uncertainty of interatomic potentials’ parameters and formalism

A sensitivity analysis of the modified embedded atom method (MEAM) potential for body-centered-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.