Advertisement

Thermo-optic behaviour of solids

V. Alkali halides
  • G. N. Ramachandran
Article

Summary

A direct verification of the general theory of thermo-optic behaviour has been obtained by applying it to the alkali halides. Rocksalt, sylvine and potassium iodide have been considered in detail. For this purpose, new dispersion formulæ embodying observed absorption frequencies have been developed for NaCl and KI. With KI, it is found that the proportionate variation χ [=−d (logv)/dt] of the first ultra-violet frequency at 2190 Å.U. measured by Fesefeldt agrees with what is calculated from thedn/dt data, thus verifying the fundamental basis of the author’s theory. The theory successfully explains the whole course of the variation ofdn/dt with wavelength in the case of rocksalt, and in particular the positive values ofdn/dt near about 2000 Å.U. and its reversal in sign with increase of wavelength. The first three ultra-violet frequencies have χ’s of the order of +100×10−6, +25×10−6 and − 30×10−6 respectively, the last one near 500 Å.U. not varying with temperature. With sylvine,dn/dt measurements in the visible and near infra-red are satisfactorily explained with similar values of χ as in rocksalt. The paper also contains a general review of the dispersion data for the alkali halides. It is shown that a dispersion formula of the Drude form is more appropriate for these salts than one of the Lorentz-Lorenz form.

Keywords

Rocksalt Potassium Iodide Dispersion Frequency Alkali Halide Sylvine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    BarnesZeits. f. Phys., 1932,75, 723.CrossRefGoogle Scholar
  2. 2.
    — and CzernyIbid.,, 1931,72, 447.CrossRefGoogle Scholar
  3. 3.
    BornAnn. d. Phys., 1918,55, 177.Enz. d. Math. Wiss., 1922,5, pt. 3, 529.CrossRefGoogle Scholar
  4. 4.
    EwaldAnn. d. Phys., 1916,49, 1, 117.CrossRefGoogle Scholar
  5. 5.
    FesefeldtZeits. f. Phys., 1930,64, 623.CrossRefGoogle Scholar
  6. 6.
    ForrestJourn. Opt. Soc. Am., 1942,32, 382.CrossRefGoogle Scholar
  7. 7.
    Fuchs and WolfZeits. f. Phys., 1928,46, 506.CrossRefGoogle Scholar
  8. 8.
    GoldhammerDispersion and Absorption of Light, Leipzig, 1913, 65.Google Scholar
  9. 9.
    GundelachZeits. f. Phys., 1931,66, 775.CrossRefGoogle Scholar
  10. 10.
    GyulaiIbid., 1927,46, 80.CrossRefGoogle Scholar
  11. 11.
    Herzfeld and WolfAnn. d. Phys., 1925,78, 35.CrossRefGoogle Scholar
  12. 12.
    Hilsch and PohlZeits. f. Phys., 1930,59, 812.CrossRefGoogle Scholar
  13. 13.
    HohlsAnn. d. Phys., 1937,29, 433.CrossRefGoogle Scholar
  14. 14.
    KorthZeits. f. Phys., 1934,84, 677.CrossRefGoogle Scholar
  15. 15.
    KublitzkyAnn. d. Phys., 1934,20, 793.CrossRefGoogle Scholar
  16. 16.
    LiebischPhysikalische Krystallographie, Leipzig, 1891, 91.Google Scholar
  17. 17.
    LiebreichVerh. d. Deutsch. Phys. Ges., 1911,9, 1.Google Scholar
  18. 18.
    MartensAnn. d. Phys.; 1901,6, 603; 1902,8, 459;Landolt-Bornstein Tables, Hauptwerke, II, 1923, 912.CrossRefGoogle Scholar
  19. 19.
    MicheliAnn. d. Phys., 1902,7, 772.CrossRefGoogle Scholar
  20. 20.
    Mott and GurneyElectronic Processes in Ionic Crystals, Oxford, 1940, 95.Google Scholar
  21. 21.
    ParlinPhys. Rev., 1929,34, 81.CrossRefGoogle Scholar
  22. 22.
    PaschenAnn. d. Phys., 1908,26, 120.CrossRefGoogle Scholar
  23. 23.
    Posnjak and WyckoffJ. Wash. Acad., 1922,52, 245.Google Scholar
  24. 24.
    PulfrichWied. Ann., 1892,45, 609.Google Scholar
  25. 25.
    Ramachandran, G. N.Proc. Ind. Acad. Sci., A., 1947a,25, 266; 1947b,25, 280; 1947c,25, 286.Google Scholar
  26. 26.
    Ramaseshan, S.Ibid., Proc. Ind. Acad. Sci., A., 1947,25.Google Scholar
  27. 27.
    Rubens and NicholsWied. Ann., 1897,60, 45.Google Scholar
  28. 28.
    — and TrowbridgeIbid.,, 1897,60, 733;61, 224.Google Scholar
  29. 29.
    Schneider and O’BryanPhys. Rev., 1937,51, 293.CrossRefGoogle Scholar
  30. 30.
    SeitzPhysics of Crystals, Mc Graw-Hill, 1940.Google Scholar
  31. 31.
    SpangenbergZeits. f. Krys., 1923,57, 494.Google Scholar
  32. 32.
    SprockhoffN. Jahrb. Min., 1903,18, 120.Google Scholar
  33. 33.
    Topsoe andAnn. d. Chem. Phys., 1874,1, 21, 30. ChristiansenAnn. d. Phys. Erg., 1874,6, 578.Google Scholar
  34. 34.
    TrowbridgeWied. Ann., 1898,65, 612.Google Scholar
  35. 35.
    Winchell “The microscopic characters of artificial inorganic substances and of artificial minerals,” 2 Ed. New York, 1931. “See Landolt-Bornstein Tables”, III Erg., 1935, p. 1501.Google Scholar
  36. 36.
    Wulff and AndersonZeits. f. Phys., 1935,94, 28.CrossRefGoogle Scholar
  37. 37.
    — and SchallerZeits. f. Kryst., 1934,87, 43.Google Scholar

Copyright information

© Indian Academy of Sciences 1947

Authors and Affiliations

  • G. N. Ramachandran
    • 1
  1. 1.Department of PhysicsIndian Institute of ScienceBangalore

Personalised recommendations