CARBON-MONOXIDE OXIDATION ON RH(111) - VELOCITY AND ANGULAR-DISTRIBUTIONS OF THE CO2 PRODUCT

The velocity and angular distributions of CO2 produced by CO oxidation on Rh(111) have been measured as a function of surface temperature an d oxygen coverage. Both the velocity and angular distributions are bim odal. The velocities of one component are well fit by a Maxwell-Boltzm ann distribution at the surface temperature, and the angular distribut ion of its intensity is cosine. The second component is non-Boltzmann, and the angular distribution is sharply peaked toward normal. The ave rage energy of this feature is a very strong function of the surface t emperature, increasing with a slope of 8.7k(b), where k(b) is the Bolt zmann constant, between 475 K and 700 K. Surprisal analysis proves use ful in condensing and interpreting these data. (C) 1995 American Insti tute of Physics.