The development of techniques for the study of photoemission from colored ionic crystals have led to a new method for measuring energy levels of electrons trapped in the crystal lattice. Some particular aspects of electron emission spectra (EES) from KCl, CsCl, and RbBr which are due to the Joshi effect or the other perturbing agents are explained. Characteristic EES for the Li, Na, K, Rb, and Cs halides, obtained by this method, are described. The values of λmax are compared with those predicted theoretically by Ivey or obtained by optical spectroscopy. The electron transfer between the F and M levels in potassium fluoride is analyzed.
Die Exoelektronen-Emissionsspektren (Emission als Funktion der Wellenliinge der stimulierenden Strahlung) von polykristallinen NaC1-, KC1-, RbCl-und CsC1-Proben wurden analysiert. Die Niveaus der Hauptzentren (F-Zentren), der Sekundarzentren (M-Zentren usw.) und deren BiIdung und Entwicklung unter der Bestrahlungseinwirkung wurden untersucht. Desgleiohen wurden auch die 3'und M-Zentren an RbCl-KCl-Mischkristallen beobachtet.The spectra of exoelectron emission (as a function of the wavelength of the exciting radiation) of polycrystalline NaC1, KCI, RbCl and CsCl samples are measured. The levels of the principal centres (F-centres), and secondary centres (M-centres etc.), as well as their formation and development under the action of radiation, are investigated. Further studies are made on F-and M-centres of RbC1-KC1-mixed crystals.
The photostimulated electron emission spectra of CaF,, SrF,, and BaF, crystals, coloured by electron bombardment, are analysed. The comparison with optical absorption spectra leads to some conclusions with respect to the kind of colour centres corresponding to the various bands observed. The results verify a relation of the Mollwo-Ivey type. Some complex bands are resolved. Sont analysBs les spectres d'Bmission electronique photostimulee des cristaux de CaF,, SrF, et BaF, color& par bombardement Blectronique. La comparaison avec les spectres d'absorption optique conduit A certaines conclusions concernant le genre de centres colorBs correspondant aux diverses bandes observbes. Les rBsultats verifient une relation du type Mollwo-Ivey. Certaines bandes complexes sont rBsolues.
The photoemission spectra of NaI, KI, RbI and CsI are investigated experimentally. Besides the bands already revealed by optical absorption measurements and confirmed by photoemission studies, the L,-L,-bands in NaI, the L,-band in RbI, and the fine structure of the El-bands in K I and RbI are observed. I n CsI electron emission is detected corresponding to the first exciton band in the absence of F-centres. The very intense "extra"-bands occurring in the absorption spectra are not found.On a analys6 au moyen de spectres de photobmission des cristaux de NaI, KI, RbI et CsI. En plus des bandes d6ja r6v616es par absorption optique et confinnbes par photobmission, ont 6th mises en 6vidence lea bandes Lx-L4 du NaI, la bande L4 du RbI e t la structure fine des bandes El du K I et RbI. Pour le CsI on a dbtect6 1'6mission dectronique en absence des centres F et on a remerqub que les trbs intenses "extra"-bandes, qui apparaissent dans les spectres d'absorption, ne s'observent pas en photobmission.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.