Variational Monte Carlo calculations for spin-aligned deuterium

The first variational Monte Carlo calculations of the ground-state energy of spin-aligned deuterium D are presented. Using Slater-Jastrow trial wave functions, the calculations are based on the accurate theoretical pair potential of Kolos and Wolniewicz for the bu3+ state. For D with equal population of the three nuclear-spin states, the minimum theoretical ground-state energy is found to be negative, implying that this system is a liquid at zero temperature under zero external pressure.