ABSTRACT
Local-spin-density-approximation molecular-dynamics simulations of deuterium in the dissociating regime are presented, with a particular emphasis on the molecular phase of two isochores corresponding for deuterium to V=6 cm(3)/mole, rho=0.670 g/cm(3) and V=4 cm(3)/mole, rho=1 g/cm(3). It is shown that the transition from the molecular regime, well described by the local-spin-density-approximation functional, to the dissociated regime where previous local-density-approximation results are recovered, comes with a negative curvature deltaP/deltaT<0 in the isochore. We show that this effect is not enough to explain the large compressibility measured in the laser experiments [L. B. DaSilva et al., Phys. Rev. Lett. 78, 483 (1997); G. W. Collins et al., Science 281, 1178 (1998); P. Celliers et al., Phys. Rev. Lett. 84, 5564 (2000)].
ABSTRACT
We present and assess a multiscale recursion method to calculate electronic density via the Green's function. The method lies within the framework of finite temperature density functional theory and uses a real space approach. It provides a satisfactory description of the first Brillouin zone without invoking k points. Unlike methods that explicitly calculate eigenstates, the computational workload decreases with temperature. Tests are performed on a system representing a hydrogen plasma with a local pseudopotential. Calculations are distributed on real space grids with different spacings using scaling properties of the recursion. The computational workload increases linearly with the size of the system and can be productively dispatched on an arbitrarily large number of processors.
