H sub 2 O adsorption on Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 (001)

Photoemission results show that water is physisorbed on a single-crystalline (001) face of the high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} at 90 K. A simple model of the electronic structure, in which Bi III lone-pair electrons protrude from the surface, is suggested to account for the stability of this surface ultrahigh vacuum compared with other oxide superconductors.