Ab initio molecular orbital study on the H2 loss reaction from ethane cation, C2H6+

Ab initio molecular orbital calculations were carried out for the H2 loss reaction from ethane cation, C2H6+. Two transition states and two intermediate products were found at the UMP2/6-311G(d,p) level of theory. RRKM calculations were also carried out and it was revealed that quantum mechanical tunneling slightly reduces the reaction threshold energy, which is due mainly to a small imaginary frequency of transition state. The reaction threshold energy estimated in this work agrees well with the experimental value obtained by Weitzel et al. [Ber. Bunsenges. Phys. Chem. 97 (1993) 134].