Accession Number : ADA118801

Title :   Absorption Coefficient of Alkali Halides. Part I.

Descriptive Note : Interim rept. 1 May 78-30 Apr 79,


Personal Author(s) : Li,H H

Full Text :

Report Date : Mar 1979

Pagination or Media Count : 262

Abstract : Data on absorption coefficients of alkali halides were compiled and analyzed. The bulk of available data were concentrated to the absorption edges of the main transparent region and were for the seven materials LiF, NaF, NaCI, KC1, KBr, KI, and CsI. Although the intrinsic absorption can be calculated by using the exponential dependence of absorption coefficient on frequency, discrepancies occur in the region where absorption is extremely low. At low absorption levels, extrinsic absorptions due to impurities and surface contamination dominate the intrinsic absorption by factors ranging from fractions to factors by ten. Experience has shown that extrinsic contributions can be reduced through improved crystal preparation. Another possible reason for the discrepancies may be the limit of instrument sensitivity. The results of this work on the alkali halides are given in two separate reports. Presented in this report are essentially the up-to-date knowledge of available data and the recommended room-temperature values of absorption coefficient in the laser wavelength and multiphonon absorption region. In the second report, results on the data analysis and theoretical studies for the temperature dependence of absorption coefficient will be given.

Descriptors :   *Alkali metal compounds , *Halides , *Absorption coefficients , Constants , Photon cross sections , Ultraviolet spectra , Correlation techniques , Data processing , Phonons , Computations , Surface chemistry , Impurities , Crystal growth , Crystal defects

Subject Categories : Inorganic Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE