Luminescence of F Centers in Alkali Halides under Hydrostatic Pressure Brothers, A. D. Lynch, David Lynch, David
dc.contributor.department Physics and Astronomy 2018-02-15T18:02:29.000 2020-06-30T06:17:32Z 2020-06-30T06:17:32Z Sun Jan 01 00:00:00 UTC 1967 2015-01-15 1967-12-01
dc.description.abstract <p>F-center luminescence spectra have been measured at 78°K in NaCl, KCl, KBr, KI, RbCl, and CsBr under hydrostatic pressure to 3.5 kbar. From a comparison between the shift of the emission peak with pressure and the shift with temperature, it is concluded that most of the latter arises from the electron-lattice interaction and not from thermal expansion. This is the opposite of the conclusion for F-center absorption, for which thermal expansion dominates the temperature coefficient of the peak energy. The halfwidth of the function W(E), the probability per unit time of emitting a photon with energy between E and E+dE, does not vary with pressure in NaCl, KCl, and RbCl, but the half-width of the "shape function," E−3W(E), changes with pressure. This is interpreted as meaning that for F-center emission, it is more suitable to make the Condon approximation on the momentum operator than on the position operator. Lifetime measurements in KCl under pressure at 15 and 78°K give the pressure derivative of the thermal ionozation energy of the relaxed excited state of the F center in KCl, + 19×10−6 eV bar−1. The pressure coefficients of a few K- and L-band peaks have been determined. These provide additional evidence that the final states in the L-band transitions are not similar to those for F- and K-band transitions. The K band in RbCl changes shape with pressure. The FA-band splitting has been found to increase with pressure in KCl:Na. The F-center emission in KBr under pressure has been found to have two components, and the excitation spectrum has two peaks, the F band and a peak very close to the K′band previously found in absorption at much higher pressures. Emission data at 12°K on diverse samples of additively colored KBr strongly suggest that there are two components to the normal F-center luminescence in KBr with no applied pressure.</p>
dc.description.comments <p>This article is from <em>Physical Review</em> 164 (1967): 1124, doi:<a href="" target="_blank">10.1103/PhysRev.164.1124</a>. Posted with permission.</p>
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dc.identifier archive/
dc.identifier.articleid 1010
dc.identifier.contextkey 6530629
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath physastro_pubs/18
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 21:33:00 UTC 2022
dc.source.uri 10.1103/PhysRev.164.1124
dc.subject.disciplines Atomic, Molecular and Optical Physics
dc.subject.disciplines Physics
dc.subject.keywords electron-lattice
dc.subject.keywords excitation spectrum
dc.title Luminescence of F Centers in Alkali Halides under Hydrostatic Pressure
dc.type article
dc.type.genre article
dspace.entity.type Publication
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relation.isOrgUnitOfPublication 4a05cd4d-8749-4cff-96b1-32eca381d930
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