Detailed theoretical photoelectron angular distributions for LiF(100)

We model photoelectron angular distributions obtained earlier by Himpsel et al, [Phys. Rev, Lett. 68, 3611 (1992)] for the F 2p bands in LiF(100). The F 2p states are treated within a many-body, quasiparticle approach, and a nearly-free-electron model is presented for the description of conduction-band states relevant to the photoemission process. In the quasiparticle results, we find a band gap of 14.4 eV and a F 2p bandwidth of 3.6 eV, in satisfactory agreement with experimental values of 14.2 and 3.5 eV for these respective quantities. A method for computing photoelectron angular distributions is presented, followed by a comparison of simulated and measured photoelectron angular distributions for several parts of the three-dimensional Brillouin zone. In this comparison, constant-energy contours in the F 2p bands are clearly portrayed in both theoretical and experimental images. Using the model, we also identify the origin of a Brillouin-zone-dependent intensity variation for equivalent valence states, i.e., states which are related by reflection through a (010)-type Bragg plane and which lie close to such a plane.