Vibrational spectra and analytical potential energy functions of some electronic states of Na2

The improved variational algebraic energy consistent method (VAECM) is suggested to study the vibrational spectra and analytical potential energy functions of six excited electronic states [Formula: see text], 2 1 Δ g , (5d) 1 Δ g , (6d) 1 Δ g , (7d) 1 Δ g , and (8d) 1 Δ g of Na 2 . The full vibrational energies, the vibrational spectroscopic constants, the force constants f n , and the expansion coefficients a n of the potential are tabulated. The VAECM analytical potential energy function with adjustable parameter λ for each electronic state is determined. The full vibrational energies of each of these electronic states correctly converge to its dissociation energy and have no artificial barrier in all the calculation ranges. The VAECM analytical potentials excellently agree with the Rydberg–Klein–Rees potentials.