NO DISSOCIATION ON RH(110)

The dissociation kinetic of NO on Rh(110) has been studied for tempera tures ranging from 198 to 240 K and NO coverages less-than-or-equal-to 0.3 ML. Auger lineshape analysis has been used to measure the amount of undissociated NO, theta(NO), as a function of time, t, at a given r eaction temperature. The constructed theta(NO)(t) plots for different reaction temperatures showed that the initial dissociation rate obeys first-order kinetics with E(a) = 4.9 +/- 0.4 kcal/mol and nu = 1 x 10( 2.5 +/- 0.5) s-1. The compositional and structural changes at various reaction temperatures, determined by parallel LEED and TPD measurement s, were considered to explain the surprisingly low kinetic parameters we obtained.