Production of HNC from the CH(X2Π) + NH(X3Σ−) reaction: Direct dynamics study

The production mechanism and dynamics of the HNC molecule from the radical-radical CH + NH reaction on the lowest doublet potential energy surface has been theoretically studied using electronic structure calculations. We have applied a direct dynamics simulation technique at the B3LYP/6-311++G(d,p) level of theory. The accuracy of the B3LYP-level potential energy surface was systematically confirmed from the comparison to more accurate MRCI-level and CCSD(T)-level calculations. More than 250 classical trajectories were integrated and we have found that the CH + NH reaction somewhat favors the HNC + H production channel over the HCN + H production despite that the energy level of HCN + H is lower than that of HNC + H. Detailed reaction mechanisms will be discussed on the basis of the trajectory results.