Rotation-vibration spectra for ground state of NaH and its isotopes with explicitly multireference configuration interaction method

High-level ab initiocalculations utilizing explicitly correlatedmulti-reference configuration interaction method (MRCI-F12), considering Davidson modification(Q), core-valence correlation correction(CV) and scalar relativistic correction(SR), were per- formed to compute the Born-Oppenheimer potential energy curve (PEC) of the ground state X 1 S + of NaH. On the base of the PEC, we obtained vibrational and rotational energy levels information of the ground state X 1 S + . The vibrational and rotational spectroscopic constants of X 1 S + were compared with the available experimental val- ues. We also report rotation-vibration spectra of the ground state for the isotopes of NaH, NaD and NaT molecules. The equilibrium internuclear distances Re and dissoci- ation energies De were calculated to be 1.8865u Aand 15823.29cm 1 for the ground state X 1 S + of NaH, which are in good agreement with the experimental results of 1.8859u A and 15815±5cm 1 .