Evidence for the observation of surface states at the Cu(110)/electrolyte interface

The reflection anisotropy (RA) spectral profiles of the interfaces between Cu(110) surfaces and H 2 O, H 2 SO 4 and HCl show a sharp positive feature at 2.2 eV that is identified with a transition between surface states at the -point of the surface Brillouin zone. In HCl this peak is narrow, its position is independent of applied potential and its intensity grows with increasing potential. The RA spectra of these interfaces also show a broad negative feature at 4.2 eV similar to that associated with [001] steps on atomically rough Cu(110) surfaces in UHV.