Static and dynamic anomalies in the Gaussian core model liquid

We investigated static and dynamic liquid-state anomalies of a single-component system interacting via a Gaussian core potential. Anomalies are produced due to the fact that the potential is bounded. Based on standard Monte Carlo simulations, we developed an equation of state for an extended phase space. From this, we were able to derive anomalies for the isothermal compressibility, the thermal expansion coefficient, as well as the specific heat very similar to the situation in liquid water. Using the pair correlation function, we detected structural peculiarities when the dimensionless density became greater than approximately 0.23. The self-diffusion coefficient is studied by means of the mean squared displacement and the Green-Kubo formula calculated from molecular dynamics simulation. This dynamic property again shows anomalous behaviour when the dimensionless density becomes greater than approximately 0.33. The behaviour can be explained by increased mobility of the particles. (c) 2006 Elsevier B.V. All rights reserved.