Structural Properties of Nitromethane Molecular Crystal under High Pressure:An ab initio Investigation

The pressure-dependent structural properties under hydrostatic pressure up to 120 GPa and the decomposition under uniaxial compression along the b lattice vector up to 40 GPa of nitromethane molecular crystal using ab initio method are presented.The internal molecular bond lengths and bond angles were calculated for different pressures.All bond lengths decrease as the pressures are increased under hydrostatic compression.The obvious rotation of methyl group is 33.89° under hydrostatic pressure at 120 GPa.In addition,we observe the change of C-H bonds,which have been stretched under uniaxial compression along b lattice vector in the range of 0～40 GPa of nitromethane.