Character of the pair interaction in solid and gaseous H2

Existing theoretical H2 pair potentials are investigated. We develop a spherically symmetric potential applicable to solid H2. It yields a ground-state energy of -98.7 K (experimental values range from -93.5 to -101 K). Pressure-volume data are also in excellent agreement with experiment between 0 and 25 kbar. Second virial coefficients using this potential are consistently too low. When an anisotropic pair potential is used, agreement becomes very good.