Wave packet molecular dynamics simulations of hydrogen under extreme conditions

With the aid of "Wave Packet Molecular Dynamics" (WPMD) simulations we inve stigate hydrogen under extreme conditions. In this model the protons are tr eated as classical point-particles, whereas the electrons are represented b y antisymmetrized wavepackets following a pseudo-hamiltonian dynamics. For the simulations we use 512 particles in a periodically continued cubic box. The equation of state, i.e. the pressure p as function of the temperature T for an electron density n = 2 x 10(29) m(-3) is rather Bat around 12,000 K. In this regime the molecules dissociate. The linear mixing model shows a t lower absolute values a more pronounced behaviour of the pressure. The ne w path integral Monte Carlo results for T > 10,000 K show a similar Batteni ng, while the tight-binding model shows hardly any. A comparison of our WPM D results with experiments for p(n) at T = 300 K shows the importance of an tisymmetrization, (C) 2001 Elsevier Science B.V. All rights reserved.