Stability of solid atomic nitrogen phases at atmospheric pressure

Stability to the formation of vacancies in the bulk of a structure and the possibility of a stable surface have been examined for the first time with density functional theory for high energy density solid atomic nitrogen phases, whose dynamical stability at normal pressure is theoretically predicted. It has been shown that phases with of the $P\bar {6}2c$ and $Pccn$ crystal symmetries are unstable to the formation of vacancies at atmospheric pressure. The $R\bar {3}$ and $P2_1$ phases are stable with respect to the formation of vacancies, but the surface of such structures introduces instability inducing their transition from a metastable atomic solid phase to a molecular one. The gauche phase of nitrogen with the $I2_13$ crystal symmetry is stable with respect to the considered structural perturbations and is the most promising for experimental synthesis at atmospheric pressure.