Simulation of thermodynamic properties of dense deuterium plasma by Monte Carlo methods

In this work we present new results of calculations of thermodynamic properties of dense deuterium plasma. We use two different methods: path-integral Monte Carlo method in a cubical cell with periodic boundary conditions and classical reactive Monte Carlo. The first approach is based upon the Feinman formulation of quantum mechanics and is applicable at any coupling parameters. To correctly take into account exchange effects at high values of the degeneracy parameter we applied a special correcting procedure which considered these effects not only in the main Monte Carlo cell but also in its nearest images. It allowed us to increase significantly the accuracy of computations at relatively high densities. Path integral Monte Carlo can't be used at temperatures below 104 K because of computational difficulties. At low temperatures we apply the second approach which accurately takes into account dissociation of deuterium molecules and interaction between all particles but neglects ionization. Our computations include isotherms, isen- tropes and shock Hugoniots. We analyze recent experiments on quasi-adiabatic and shock compression of deuterium in Sarov, Russia and discuss the influence of dissociation and quantum effects on thermodynamic properties of deuterium. We also consider the problem of possible dissociative phase transition in deuterium at temperatures 5000 K and pressures 1 Mbar.