RRKM STUDIES OF PRODUCT BRANCHING IN THE NH+NO REACTION

We use RRKM theory to calculate rate constants and product branching f ractions for NH + NO, comparing results for an ab initio surface and t wo recent empirical surfaces. In addition we compare trajectory and RR KM branching fractions based on the empirical surfaces, including an a ssessment of zero-point energy effects on branching. Our calculations show that the ab initio and empirical surfaces give similar branching, with results that are in good agreement with recent experiments. Traj ectory and RRKM branching results are also close, but the HNNO lifetim es are not. Anharmonic effects are a possible explanation of this disc repancy.