NUKLEONIKA 2002, 47(Supplement 1):s81-s84

 


THEORETICAL STUDY OF KINETIC ISOTOPE EFFECTS ON HYDROGEN ABSTRACTION REACTIONS



Yuzuru Kurosaki

Advanced Photon Research Center, Japan Atomic Energy Research Institute,
Umemidai, Kizu-cho, Soraku-gun, Kyoto 619-0215, Japan


Effects of isotopic substitutions of "spectator" hydrogens on rate constants have been theoretically examined for the CH3 + H2 CH4 + H (I) and C2H + H2 C2H2 + H (II) reactions using variational transition state theory with the multidimensional semiclassical tunneling correction. A small but significant secondary isotope effect was found for reaction (I) but almost no isotope effect was found for reaction (II). This is bacause the potential energy surface for reaction (II) has an "early" character.


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