Primary and secondary kinetic isotope effects for methoxy dehydrogenation and Cu(110): Absence of tunnelling corrections

The primary, secondary and total kinetic isotope effects for dehydrogenation of methoxy adsorbed on Cu(110) has been determined. Heating rate variation plots reveal all kinetic isotope effects clearly. The value of the primary isotope effect at 300 K is 5.5, and its value is governed by zero point energy differences. The secondary isotope effect is unity within experimental error, and the total effect is entirely accounted for by elementary transition state theory without any tunnelling corrections.