A potential energy surface for the electronic ground state of N2O

A potential energy surface for the electronic ground state of N2O is optimized using a variational procedure with an exact vibrational Hamiltonian. In the optimization, the ab initio force field of Martin, Taylor and Lee is taken as a starting point, and the observed vibrational band origins up to 15000 cm−1 reported by Campargue and co-workers are involved. The RMS error of this fitting to the 60 observed Σ state vibrational energy levels is 0.34 cm−1. The rovibrational energy levels for the Σ and Π vibrational states are calculated to test the refined potential.