Theoretical characterization of the 5Π and 3Π potential energy surfaces for NH+O→N+OH.

The reactant, product, and saddle point regions of the 5Π and 3Π potential energy surfaces for the reaction NH+O→N+OH have been characterized using complete active space self consistent field/externally contracted configuration interaction (CASSCF/CCI) calculations with large atomic natural orbital (ANO) basis sets. The computed barrier heights are 5.6 and 11.7 kcal/mol on the 5Π and 3Π surfaces, respectively. Transition state theory with an Eckart tunneling correction is used to estimate the rate constant on the 5Π surface. [ABSTRACT FROM AUTHOR]