HYDROXYL FORMATION ON AG(110) STUDIED BY HREELS

The coadsorption system Ag(110)-O/H2O is known to give rise to well de fined OH layers in a thermally activated process between 190 and 220 K . In a high resolution EELS study we have found that the (1 x n), n = 3,2 ordered layers produced from the (n x ii, n = 6,4 reconstructed Ag (110)-O surface are characterized by very sharp loss peaks at 277 cm(- 1) (v(M-OH)) and 3390 cm(-1) (v(O-H)). The dominant M-OH loss exhibits essentially the same halfwidth as the specular peak, whereas the OH b ending mode at 675 cm(-1) is significantly broadened and shows a shoul der at 755 cm(-1). The (1 x 1)-OH phase formed from the (2 x 1)-O reco nstructed phase is less stable than the lower coverage OH layers. Such studies may play an important role in understanding the mechanism of this almost unique stoichiometric reaction.