THE LOCAL ADSORPTION GEOMETRY OF OXYGEN ON PT(210) - A SEXAFS STUDY

Polarisation-dependent surface-extended X-ray-absorption fine-structur e (SEXAFS) experiments have been performed on the Pt(210)-(5 X 2)rect- O system. The analysis shows that single 3-fold coordinated adsorption sites and mixtures of different 3-fold sites with a nearest-neighbour O-Pt bond length of R = 1.79 +/- 0.05 Angstrom on both microfacets - (110) and most likely (310) - can reproduce the results. A mixture of different sites consisting of 3-fold coordinated sites on (110) and hi gh-symmetry sites of other than 3-fold coordination on (310) must be e xcluded.