Hydrogen abstraction reactions
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract Five hydrogen abstraction reactions, CH4 + R → CH3 + HR have been studied usingab initio SCF and CI methods. R was successively chosen as H, CH3, NH2, OH and F. Geometries were fully optimized at SCF level and energies were computed at CI level for products, reactants and transition states. Quadratic hypersurfaces were fitted in the neighborhood of the most important points of the potential energy hypersurfaces and vibrational analysis were performed thereupon. Wigner's and Christov's approximations were used to obtain an idea of the importance of tunneling of H atoms through the reaction barrier, and this effect was shown to be non-negligible. Finally, rate constant calculation were carried out at different temperatures.
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