Density-functional study of nonmolecular phases of nitrogen: Metastable phase at low pressure

In first-principles variable-cell-shape molecular dynamics simulations and structural optimizations of nitrogen at pressures of 0–500 GPa, the phase with lowest enthalpy at high pressures, BP, was found to transform at low pressures into a new, metastable, metallic phase with a chainlike structure. The latter may possibly be related to a metastable nonmolecular phase that was recently observed experimentally at low temperatures and pressures.