Ni(100) has been exposed to O-2 to form similar to 3 monolayer crystal
line NiO(111) thin films and the films have been characterized by HREE
LS, XPS, AES and acetic acid adsorption. The NiO(111) is Ni2+-polar an
d contains approximately 65% of the surface nickel sites terminated by
isolated OH with substantial ionic character. The hydroxyls appear to
serve a stabilizing role for the thermodynamically metastable NiO(111
) surface and also to provide a condensation mechanism for interaction
with the acetic acid. While there are Ni2+-OHads surface sites availa
ble for adsorption, at least some of the hydroxyls associated with the
NiO(111) film are occluded or otherwise inaccessible. The XP and HREE
L spectral data support an assignment of adsorbate formation to a brid
ging acetate species.