Two-directional N-2 desorption in thermal dissociation of N2O on Pd(110) at low temperatures

The angular distribution of desorbing N-2 was studied in the thermal decomp osition of N2O(a) on Pd(1 1 0). N2O(a) was mostly decomposed during heating procedures, emitting N-2(g) and leaving O(a). N2 showed four desorption pe aks, beta (1)-N-2 around 150 K, beta (2)-N-2 around 134 K, beta (3)-N-2 at 123 K, and beta (4)-N-2 at 110 K. The first peak was found at high N2O expo sures and the last at low exposures. Both beta (1)-N-2 and beta (3)-N-2 rev ealed inclined emission at +43 degrees and -43 degrees off the surface norm al in the (0 0 1) plane, beta (4)-N-2 sharply collimated around +50 degrees and -50 degrees, and beta (2)-N-2 showed a cosine distribution. (C) 2001 E lsevier Science B.V. All rights reserved.