Ab initio molecular orbital dynamic reaction path simulations of HNC <-> HCN isomerization reaction: election of the reaction mode in a thermally excited system

摘要

Dynamic reaction path (DRP) simulation of the HNC <-> HCN isomerization reaction has been carried out at the HF/6-31G~(**) level to search for an intramolecular vibrational energy redistribution (IVR) process converging to the reaction mode of vibration having an imaginary frequency near the transition state (TS). Starting at the TS, a molecule was pushed forward or backward with the least necessary excess energy in the direction of the reaction mode. The thus started DRP, proposed here as intrinsic dynamic reaction path (IDRP), was analyzed in terms of vibration mixing and vibration mapping methods, giving an example of the IVR process to build up the reaction mode from randomly distributed vibration modes.