High-precision evaluation of the vibrational spectra of long-range molecules

Vibrational spectra of long-range molecules are determined accurately and to arbitrary accuracy with the Canonical Function Method. The energy levels of the 0-g and 1u electronic states of the 23Na2 molecule are determined from the ground state up to the continuum limit. The method is validated by comparison with previous results obtained for different potentials adapted to long-range molecules.