The ground state properties of spin-aligned atomic hydrogen, deuterium, and tritium

The bulk, ground state properties of atomic hydrogen, deuterium, and tritium systems are calculated assuming that all pair interactions occur via the 3Σ+u atomic triplet potential. The conditions required to obtain this system, including inhibition of recombination through the energetically favorable singlet interaction, are discussed. The internal energy, pressure, and compressibility are calculated over the volume range 40 cm3/mole ? V ⩽200 cm3/mole applying the Monte Carlo technique with a quantum mechanical variational wavefunction. The system studied consisted of 32 atoms in a box with periodic boundary conditions. Results show that atomic triplet hydrogen and deuterium remain gasous at 0 K; i.e., the internal energy is positive at all molar volumes considered. Under the same conditions, tritium forms a liquid with a binding energy of E0 ? −0.75 K per atom, at a volume of V ? 130 cm3/mole. The pair distribution function for these systems is also calculated. A brief discussion of the predicted superfluid behavior of 3Σ+u hydrogen and tritium is presented.