Density functional calculations with simulated annealing—isomers of S₇X [X  O, S, Se], Se₈, O₈

Density functional calculations—with a local density approximation for the exchange and correlation energy—provide a numerically efficient method for determining total energy variations in molecules. Coupled with molecular dynamics techniques such as simulated annealing, they provide a scheme for probing large regions of configuration space in molecules. We outline the main features of the method and apply it to different ring isomers of S₇O, S₈, S₇Se, Se₈, and O₈.