The adsorption of hydrogen on Ru(11(2)over-bar1)

HREELS and TDS results are presented for hydrogen adsorption on Ru(11 (2) o ver bar1) at 90 K. Three distinct adsorption states were separated both fro m TDS and HREELS. These alpha, beta and gamma states are characterized by d esorption temperatures of 115, 175-280, 345 K. The according vibrational en ergies are (42, 95 meV), (64, 115, 160 meV) and (62, 92, 145 meV). By compa rison with literature data and taking into account the site symmetries, the se states are assigned to fourfold and threefold symmetric sites, respectiv ely. (C) 2001 Elsevier Science B.V. All rights reserved.