Comparative study of solvent-CL-20 interactions at different roughness crystal surfaces: Molecular dynamics simulation

Abstract

Abstract The 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20)-solvent (methanol, ethanol, ethyl acetate and acetone) interfacial models were constructed to investigate the intermolecular interaction variances on different roughness surfaces. The constant volume and temperature molecular dynamics (NVT-MD) simulation was performed on the interfacial models. The mass density distributions of four kinds of solvent at interfaces were calculated based on the NVT-MD results. The surface electrostatic potential (ESP) of seven important extended CL-20 surfaces were studied at the B3LYP-D level with 6-311G (D) basis set. The interaction energies ( E int ), polarities of surfaces, radial distribution function (RDF) and number of H⋯O atom pairs were analyzed. The results show the largest densities of ethanol and acetone appear at the roughest (1 1 0) surface, while generating on the smoothest (1 1 −1) and (0 0 2) surfaces for methanol and ethyl acetate. ESP at the “basin” of (1 1 0) and (1 0 1) rough surfaces are negative, benefiting for attractions of solvent positive groups. RDF analysis indicates that the rough surfaces may be more beneficial for stronger non-bond interaction formation at the solvent-CL-20 interfaces. Results of interaction energies show that E int of the roughest surface [(1 1 0) or (1 0 1)] are the largest (most negative) and relative small at the smooth (0 0 2) surface, indicating the influence of solvent on rougher face growth is more significant.