Low-lying Adiabatic Electronic States of NO: a QMC Study

Using Diffusion Monte Carlo in the fixed node approximation (FN-DMC) we have computed the electronic energy curves for some low lying doublet and quartet adiabatic states of NO. By starting with compact trial wave functions, we obtained accurate results in a wide range of internuclear distances. We have also been able to compute some spectroscopic properties and to interpret UV and visible absorption and emission spectra of NO in the gas phase by computing the Franck-Condon factors in the Born-Oppenheimer approximation. The comparison with available theoretical and experimental data is good.