Simulations of dense atomic hydrogen in the Wigner crystal phase

Path integral Monte Carlo simulations are applied to study dense atomic hydrogen in the regime where the protons form a Wigner crystal. The interaction of the protons with the degenerate electron gas is modeled by Thomas-Fermi screening, which leads to a Yukawa potential for the proton-proton interaction. A numerical technique for the derivation of the corresponding action of the paths is described. For one density of r(s) = 200 (p = 2100 g cm(-3) for hydrogen), the melting properties are studied using the Lindemann ratio, the structure factor, and free energy calculations. Anharmonic effects in the crystal vibrations are analyzed. (c) 2006 Elsevier Ltd. All rights reserved.