The intermolecular pair potentials of the dimer H2-H2 were constructed from quantum mechanics using method CCSD(T) with Dunning's correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3, 4); ab initio energies were extrapolated to the complete basis set limit. The interaction energies were corrected for the basis set superposition error (BSSE) with the counterpoise scheme. The second virial coefficients of hydrogen resulting from ab initio potential functions Đại học Đà Lạt 26-May-2009