Studying the energy hypersurface of continuous systems - the threshold algorithm

A new method is presented for the study of the structure of the energy hypersurface of continuous systems. This so-called threshold algorithm is an adaptation of the `lid method' introduced by Sibani and co-workers in 1993 (Sibani P et al 1993 Europhys. Lett. 22 479 - 85) for the investigation of discrete energy landscapes. The algorithm produces an estimate of the local densities of states near deep-lying local minima of the potential energy of the system together with the barrier heights around these minima. This allows the computation of, for example, specific heats, the estimation of the kinetic stability of configurations that represent metastable minima of the potential energy, and the description of the relaxation behaviour of the system. As an example, a two-dimensional neon crystal is studied, where for example the calculated specific heat is found to agree with the experimental values of the three-dimensional case scaled to two dimensions.