Deduction of atomic orbitals in a valence band by two-dimensional angular distribution of photoelectrons

The method to deduce the atomic orbitals constituting a valence band from t wo-dimensional photoelectron angular distribution (PEAD) (called ODAD: orbi tal determination from angular distribution) is fully discussed. The two-di mensional PEAD pattern obtained by using linearly polarized light is charac teristic of the initial atomic orbitals. If the initial electronic state is localized and a wide-angle two-dimensional PEAD pattern is observed, the c omponent ratio of atomic orbitals can be deduced by fitting the observed PE AD with calculated patterns. When only a limited area is observed by the ef fect of band dispersion, we can change the polar angle theta(P) or the azim uthal angle phi(P) of the sample with respect to the incident photon so tha t we can get enough information. Even and odd symmetries are easily disting uished when we measure the phi(P) dependence of the photoelectron intensity . The theta(P) dependence at a special direction (theta(k), phi(k)) = (45, 35) is proposed to distinguish all atomic orbitals. (C) 1999 Elsevier Scien ce B.V. All rights reserved.