Federal Republic of Germany

We have performed a study of empty electronic bulk and surface states on the three low indexed copper surfaces employing momentum resolved inverse photoemission. The bulk electronic features may be well understood in the frame work of the bulk direct transition model using state of the art band structure calculations. Surface states of both, the crystal derived and the image potential induced type have been identified and were found to agree with previous work. Several radiative transitions into unoccupied bands were also investigated at elevated temperatures. Characteristic temperatures of an exponential attenuation law are distinctly different between surface and bulk transi-tions. However, no systematic behaviour of bulk transitions at different points of the Brillouin zone could be established. I