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 rs = 200 (ρ =2,100 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.