The translational energy of desorbing products in NO and N2O decomposition on Pd (110)

• Published in: The Journal of chemical physics 1999-05, Vol.110 (17), p.8221-8224
• Main Authors: Ohno, Yuichi, Kimura, Kazushi, Bi, Ming, Matsushima, Tatsuo
• Format: Article
• Language: English
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.478733

The angular and velocity distributions of desorbing N2, N2O, and NO molecules were studied in the decomposition of NO and also N2O on a palladium (110) surface by means of angle-resolved thermal desorption combined with cross-correlation time-of-flight techniques. The results were quite similar in both cases although the desorption of N 2, N2O, and NO concurrently peaked at 490 K in the NO decomposition and, in the N 2O decomposition, the desorption of N 2 and N2O peaked at 140 K. The desorption of N2O and NO showed a cosine angular distribution and a Maxwellian velocity distribution at the surface temperature. On the other hand, the N2 desorption collimated sharply at ±41°–43° off the surface normal in a plane along the [001] direction. Then the velocity distributions of N2 involved two hyperthermal components with the mean translational energy of 0.47 and 0.22 eV, respectively. A mechanism for the inclined N2 desorption was proposed to be due to a highly exothermic reaction of N2O(ad)→N2(g)+O(ad) and the strong repulsive force operative on the product N2 from the surface.