AM1 study of the reaction between NCO and NO_2 yielding N_2O and CO_2

摘要

AM1 molecular orbital method using the unrestricted Hartree-Fock (UHF) calculation has been applied to investigate the mechanism of NCO reaction with NO_2. The geometries of the reactant, transition states, intermediates and product have been optimized and verified by frequency analysis. Zero-point energies are also corrected. The results show that this is a multi-step mechanism. Along the reaction process, there are three intermediates and four transition states. The step from IM1 to IM2 is the rate-controlling step, whose energy barrier is 193.24 kJ mol~(-1). The whole reaction is exothermic, with energy difference -285.22 kJ mol~(-1).