Influences of pressure on methyl group, elasticity, sound velocity and sensitivity of solid nitromethane

First-principles calculations were employed to investigate the influences of pressure on methyl group, elasticity, sound velocity and sensitivity of solid nitromethane. The obtained structural parameters based on the GGA-PBE +G calculations are in good agreement with theoretical and experimental data. The rotation of methyl group appears under pressure, which influences the mechanical, thermal properties and sensitivity of solid NM. The anisotropy of elasticity, sound velocity and Debye temperature under pressure have been shown, which are related to the thermal properties of solid NM. The enhanced sensitivity with the increasing pressure has been discussed and the change of the most likely transition path is associated with methyl group.