Concerning the isotope effect in the decomposition of ammonia on tungsten surfaces
It has been stated in the literature that NH3 decomposition on W being 1.6 times faster than ND3 precludes N2 desorption being the rate-determining step as has been suggested from kinetic measurements. Having found ND3 is a better electron donor than NH3 we present a simple molecular orbital model of bonding to the surface which suggests the isotope effect can be explained as a β-secondary isotope effect which is compatible with N2 desorption being rate limiting.
Sheets, Ralph, and G. Blyholder. "Isotope effect in the decomposition of ammonia on tungsten surfaces." The Journal of Physical Chemistry 76, no. 7 (1972): 970-971.
The Journal of Physical Chemistry