MRCI potential curve and analytical potential energy function of the ground state of H₂

The potential energy curve of the ground electronic state of H₂ has been calculated using valence internally contracted multireference configuration interaction calculations and augmented correlation consistent basis sets(aug-cc-pV6Z). These give bond dissociation energy D_e = 4.7446 eV, which is very close to other theoretical values in the literature. The ab initio potential energies have been fitted to analytical potential energy function (APEF) using a 5-parameter Murrell-Sorbie potential energy function. Based on the APEF, we have calculated the spectroscopic parameters of the state and compared with the experimental data available at present.