On the lattice dynamics of solid nitrogen

Lattice statics and dynamics calculations for α-nitrogen have been done using the 6-exp atom-atom interaction to derive intermolecular forces. The three parameters of this interaction are reduced to one by constraining them so that the unit cell and sublimation energy are calculated to agree with experiment. Choice of the one parameter is then made using spectroscopic data. This 'best' potential is then used to calculate the statics and dynamics of β-nitrogen. This is stable only under pressure, and the calculation of the lattice dynamics under pressure gives a satisfactory agreement with experiment.