Orientation of 10,11-dihydrocinchonidine on Pt(111)

N K-edge NEXAFS and corresponding STEX calculations have been used to examine the orientation of 10,11-dihydrocinchonidine on Pt(111) at 298 and 323 K. The results indicate that the quinoline ring system is approximately parallel to the substrate at 298 K but is tilted up from the surface by 60+/-10 degrees at 323 K. An additional feature appears in the NEXAFS at the higher temperature, which probably arises from dissociation to quinoline. These results are in line with those expected on the basis of mechanistic studies involving supported Pt catalysts. (C) 1999 Elsevier Science B.V. All rights reserved.