The water-nitric oxide intermolecular potential-energy surface revisited

摘要

The two lowest energy intermolecular potential-energy surfaces (IPESs) of the water-nitric oxidecomplex are evaluated using the spin-restricted coupled-cluster R-CCSD(T) model and theaugmented correlation-consistent polarized-valence triple-zeta basis set extended with a set of the3s3p2dlflg midbond functions. A detailed characterization of the IPESs for both the ~2A' and ~2A"electronic states in the C_s-symmetry configurations of the complex is performed. The globalminimum for the ~2A' state represented by the lowest energy of -461.8 cm~-1is deeper than theglobal minimum in the ~2A" state with an energy of -435.2 cm~-1.To explore the physics theinteraction an open-shell implementation of the symmetry-adapted perturbation theory is employedand the results are analyzed as a function of the intermolecular parameters. The electrostatic termshows the strongest geometric anisotropy, while the exchange, induction, and dispersioncontributions mostly depend on the intermolecular distance. The energy separation between the ~2A'and ~2A" states is largely dominated by electrostatic contribution for long intermolecular distances.In the region of short intermolecular distances the exchange part is as important as the electrostaticone and the induction and dispersion effects are also substantial.