Potential Energy Surface Mapping of Energetic Materials Using Coupled Cluster Theory

1,1-diamino-2,2-dinitroethylene (Fox-7) has proven to be a promising energetic material due to its low shock sensitivity and high thermal stability, and has been the subject of several Department of Defense (DoD) theoretical investigations employing Hartree-Fock and density functional theory. However, it is well-known that many energetic crystals have a significant binding contribution resulting from dispersion, a phenomena that is not accurately described by computational methods that are not explicitly correlated. This paper details the use of a state-of-the art quantum chemistry method, coupled-cluster theory, to compute a six-dimensional, dimer potential energy surface of the Fox-7 energetic molecule, which will be used to develop a pair potential for use in molecular dynamics simulations. In addition, a dimer potential energy function determined using symmetry-adapted perturbation theory is described and molecular dynamics simulations using the fitted potential are presented.