Interatomic potential parameters for molecular dynamics simulations of RDX using a reactive force field: A validation study

The parameter sets of the ReaxFF potential distributed with the open source, Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code, is validated for simulating crystal RDX. These parameters are used to model crystal RDX and obtain its unit cell size and bulk modulus. It is seen that the parameters supplied with LAMMPS (5-April, 2011 release) do not reproduce the unit cell size and bulk modulus of crystal RDX as reported by experiments and by other simulations using the ReaxFF potential. The simulation method and relevant parts of the LAMMPS code implementing the method has been earlier validated for Cu. We conclude that either the parameter sets provided with the LAMMPS distribution or its implementation of the ReaxFF potential are not suitable for modeling crystal RDX.