skip to main content

SciTech ConnectSciTech Connect

Title: AIREBO-M: A reactive model for hydrocarbons at extreme pressures

The Adaptive Intermolecular Reactive Empirical Bond Order potential (AIREBO) for hydrocarbons has been widely used to study dynamic bonding processes under ambient conditions. However, its intermolecular interactions are modeled by a Lennard-Jones (LJ) potential whose unphysically divergent power-law repulsion causes AIREBO to fail when applied to systems at high pressure. We present a modified potential, AIREBO-M, where we have replaced the singular Lennard-Jones potential with a Morse potential. We optimize the new functional form to improve intermolecular steric repulsions, while preserving the ambient thermodynamics of the original potentials as much as possible. The potential is fit to experimental measurements of the layer spacing of graphite up to 14 GPa and first principles calculations of steric interactions between small alkanes. To validate AIREBO-M’s accuracy and transferability, we apply it to a graphite bilayer and orthorhombic polyethylene. AIREBO-M gives bilayer compression consistent with quantum calculations, and it accurately reproduces the quasistatic and shock compression of orthorhombic polyethlyene up to at least 40 GPa.
Authors:
;  [1] ;  [2]
  1. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
  2. Macromolecular Science and Technology Branch, U.S. Army Research Laboratory, Aberdeen, Maryland 21005 (United States)
Publication Date:
OSTI Identifier:
22415851
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACCURACY; ALKANES; COMPRESSION; GRAPHITE; LAYERS; LENNARD-JONES POTENTIAL; MORSE POTENTIAL; ORTHORHOMBIC LATTICES; POLYETHYLENES; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; THERMODYNAMICS