A post-Hartree–Fock study of pressure-induced phase transitions in solid nitrogen: The case of the α, γ, and ε low-pressure phases

We have performed fully periodic ab initio post-Hartree–Fock calculations on three low-temperature molecular phases of solid nitrogen, namely α, γ, and ε. The aim is to characterize the pressure-induced transitions among these phases, which are prototypical molecular crystals, through a periodic local-MP2 method, implemented in the CRYSCOR program. Cohesive energies are computed using extended correlation consistent molecular basis sets, up to quintuple-ζ quality. The MP2 description of equilibrium volumes, pressure–volume curves, and transition pressures is found to be in good agreement with the experiments.