ORIENTATION AND ABSOLUTE COVERAGE OF FURAN AND 2,5-DIHYDROFURAN ON AG(110) DETERMINED BY NEAR EDGE X-RAY ABSORPTION FINE-STRUCTURE AND X-RAY PHOTOELECTRON-SPECTROSCOPY

The orientation, absolute coverage and core-electron binding energies of furan (C4H4O) and 2,5-dihydrofuran (C4H6O) on Ag(110) have been measured using near edge x-ray absorption fine structure and x-ray photoelectron spectroscopy. Both furan and 2,5-dihydrofuran (2,5-DHF) are tilted 22 +/- 7-degrees from the plane of the surface for both submonolayer and monolayer coverages. The saturation monolayer coverages on the Ag(110) surface of 0.45 +/- 0.07 ML for furan and 0.41 +/- 0.06 ML for 2,5-DHF are consistent with expectations based on van der Waals radii. The C(1s) binding energies for a monolayer of furan on Ag(110) are 284.8 and 286.2 eV, while the C(1s) binding energies for 2,5-DHF are 285.1 and 286.6 eV. The O(1s) binding energies are 532.8 and 533.8 eV for furan and 2,5-DHF monolayers, respectively. The onset of excitations from C(1s) levels to the continuum lies well above the Fermi level due to the weak bonding interactions with the surface.