Poisson's ratio of degenerate crystalline phases of three-dimensional hard dimers and hard cyclic trimers

Monte Carlo simulations of two three-dimensional hard-body models, hard dimers and hard cyclic trimers, were performed in the NpT ensemble. The Poisson's ratio was determined for degenerate crystalline phases in both systems. In contrast to the results of analogous simulations in two-dimensions, positive values were obtained both for the dimers and the trimers. However, the Poisson's ratio of the trimers was lower than that for the dimers and the latter was lower than that for the spheres. This suggests that a negative Poisson's ratio may be obtained for molecules composed of more spheres. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.