HR: 0830h
AN: T51E-0201    [PDF]
TI: Charge Releasing of Charge Trapping Centers on Milled Quartz Grains
AU: * Takeuchi, A
EM: takeuchi@curie.sc.niigata-u.ac.jp
AF: Department of Chemistry, Faculty of Science, Niigata University, Ikarashi-ninocho 8050, Niigata, 950-2181 Japan
AU: Nagahama, H
EM: nagahama@dges.tohoku.ac.jp
AF: Department of Geoenvironmental Sciences, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578 Japan
AU: Hashimoto, T
EM: thashi@curie.sc.niigata-u.ac.jp
AF: Department of Chemistry, Faculty of Science, Niigata University, Ikarashi-ninocho 8050, Niigata, 950-2181 Japan
AB: Milling treatment makes quartz grains with amorphous and/or disturbed surface layers that acquires many E' centers and is often called the surface disordered layer. We measured thermoluminescence (TL) from milled quartz grains of different sizes with and without surface disordered layers. Here, TL phenomenon from quartz is caused by recombination of thermally stimulated electrons and Al-hole centers. The TL intensities per unit mass of both grains with and without the surface disordered layers decreased with decreasing grain diameter. It is due to loss of photons through reflection on grain surfaces. In addition, the TL intensity of grains with the layers decreased more rapidly than that without the layers. This indicates deformation and/or breakage of Al-hole centers in the surface disordered layers. Broken Al-hole centers release holes, while newly formed E' centers release electrons. These holes and electrons are disturbed in surface disordered layers during the milling procedure. These charges form surface electrification on grains and generate even TL. Faulting similarly forms the surface disordered layers along fault surfaces and in the gouge. Therefore, the charge releasing of charge trapping centers may be widely related to generation of electromagnetic phenomena accompanied with earthquakes.
DE: 1000 GEOCHEMISTRY (New field, replaces Rock Chemistry)
DE: 3904 Defects
DE: 5109 Magnetic and electrical properties
DE: 5470 Surface materials and properties
DE: 6045 Physics and chemistry of materials
SC: Tectonophysics [T]
MN: 2003 Fall Meeting