Adsorption properties of ethene on Pt3Cu(111)

The adsorption of ethene on the Pt3Cu(111) surface at 95 K has been studied by high resolution electron energy loss spectroscopy (HREELS), temperature programmed desorption (TPD), low energy electron diffraction (LEED), and w ork function change measurements. While the TPD, LEED and work function cha nge measurements were presented elsewhere (C. Becker, T. Pelster, M. Tanemu ra, J. Breitbach, K. Wandelt, submitted to Surf. Sci.), in this communicati on a full peak assignment of the HREEL spectra is attempted. Two ethene spe cies were found and identified as a weakly bonded pi-complex and a stronger bonded di-sigma-complex. No ethene conversion/dehydrogenation can be found after heating the precovered surface to temperatures between 220 K and 300 K, surprisingly the di-sigma-species cannot be isolated by annealing at su bsequently higher temperatures. (C) 1999 Elsevier Science B.V. All rights r eserved.