Abstract: The ab initio calculations have been performed on the reaction paths of 1,1-and 1,2-dehy-drogenations of amino-carbene. We have determined the geometries and energies of two transition states, and obtained the activation energies, frequency factors and the activation entropies at the RHF/4-31Glevel. The vibrational correlation from the reactant to the transition state indicated that the IRC of 1,1-H₂elimination was associated with the deformation mode of 1491cm^-1, and the IRC of 1,2-H₂elimination was connected with the C-H bond asymmetrical stretching mode. The vibrational coupling between normal coordinates occuring in the 1,1-H₂elimination path was strong, and that occured in the 1,2-H₂elimination path was weak. The results provided some useful informations and introduction for the study of laser-inducing and mode-selective chemical reaction.

Key words: Ab initio, IRC analysis, Mode-selection