Calculated properties of solid N2O at various temperatures and pressures

Abstract

Properties of solid N2O at pressures P≤15 GPa and at temperatures T=0 and 300 K have been calculated using energy optimization, Monte Carlo methods in an (N,P,T) ensemble with periodic, deformable boundary conditions, and lattice dynamics. A stable Pa3 structure is predicted at zero pressure and a phase transition into an orthorhombic Cmca phase is predicted at P=4.75 GPa, with a volume change ΔV≂0.25 cm3/mole. These results are in complete agreement with experiments conducted in conjunction with this work. Calculated libron frequencies are in agreement with recent Raman measurements. In addition, second virial coefficients, lattice parameters, internal energies, and pressure-volume relations have been calculated.