(0001) quartz surface imperfections

Self-trapped excitons at the quartz(0001) surface.

We have studied self-trapped excitons in alpha-quartz using density functional theory (DFT), both in the crystal and at the (0001) surface. The excitons are triplet excited states that distort the crystal locally. They have a long lifetime, of the order of a millisecond, and become thermally equilibrated. We have calculated the drop in the exciton energy as it approaches the surface from the in...

Surface electronic structures of La(0001) and Lu(0001)

D. Wegner,1 A. Bauer,1 Yu. M. Koroteev,2,3 G. Bihlmayer,4 E. V. Chulkov,2,5 P. M. Echenique,2,5 and G. Kaindl1 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin-Dahlem, Germany 2Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Basque Country, Spain 3Institute of Strength Physics and Material Science, ...

Surface chemistry and quartz hazard.

The variability of quartz hazard is related to the characteristics of particulate toxicants. Although these have the same chemical composition, they exist in various forms and surface states, each one eliciting different biological responses. On the basis of data from the literature, surface chemical properties are associated to the subsequent stages reported by Donaldson and Borm (1998) in the...

Magnetically ordered surface oxide on Gd„0001..

Oxygen adsorption on Gd~0001! at 300 K leads to the formation of a well-ordered surface oxide with a characteristic occupied valence state, originating from hybridization between Gd 5d and O 2p states. This oxygen-induced state, which closely resembles the surface state of clean Gd~0001!, has a binding energy of '0.8 eV at Ḡ and hence permits a detailed investigation by photoelectron spectrosco...

Unoccupied surface electronic structure of Gd(0001).