Angle resolved intensity and velocity distributions of N₂ desorbed by N₂ O decomposition on Rh(110)

The angle resolved intensity and velocity distributions of desorbing product N₂ were measured under a steady-state N₂ O+CO reaction on Rh(110) by cross-correlation time-of-flight techniques. Three-dimensional intensity distribution of N₂ has been constructed from the angle resolved intensity distributions in the planes along different crystal azimuths. N₂ desorption has been found to split into two lobes sharply collimated along 50-63° off normal toward [001] and [00 1-] directions, suggesting that N₂ O is decomposed through the transition state of N₂ O adsorbed with the molecular axis parallel to the [001] direction. From the velocity distribution analysis, each desorption lobe is found to consist of two components with different peak angles, ca. 50° and 74° off normal. In both lobe cases, desorption components have been interpreted by the model of two adsorption sites; N₂ O at on-top site emits N₂ to 50° and that at bridge site emits to 74°.