Computational Vibrational and Electronic Spectroscopy of the Water Nitric Oxide Complex

The water nitric oxide complex has been studied computationally. We consider the four lowest energy structures of the H2O-NO complex: two from both symmetries (2)A' and (2)A ''. We use the coupled cluster method with correlation consistent basis sets in all ab initio calculations. Vibrational transitions have been calculated using a model that describes the complex as two individually vibrating monomer units: H2O and NO. We use the variational method to solve the vibrational problem. The OH-stretching energy levels and transition intensities are calculated up to the second and NO-stretching to the third overtone region. We also study NO-stretching vibronic transitions (A(2)Sigma(+)<- X-2 Pi). We use an isolated local mode approach to calculate energies and oscillator strengths of the vibronic transitions. The results for the complex are compared to the corresponding monomer ones.