Structure and thermodynamics of molecular nitrogen clusters

By implementing simulated annealing procedures within the Monte Carlo and steepest descendent algorithms, the potential energy surface of various N-2 clusters, (N-2)(x), in the vapour phase is explored. A functional form of the potential which include intermolecular, intramolecular, and quadrupole-quadrupole interactions is used. Results show very small distortion of the molecular component and very symmetric centre of mass structures. The N-2 molecules forming the clusters are randomly oriented in space with limited rotation of the molecular species at low temperatures. Calculation of the thermodynamic properties for these clusters shows that the formation of some of these systems is favoured by energetic contributions whereas others are formed by entropically driven reactions.