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Solid transport rate in the vapor solvent growth system ZnS:I
Vol. 1, No. 7
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS
245
ber of’ specimens of’ natural diamond, counting technique. reported The limit5a (24.5 using ±1 eV)theis conduction compared with the previously ing minimum value found for value obtained using 8-particle excitation = 18.5 ± 1.5 cv). The observed difference between and is explained quantitatively in terms of the large ratio between the a- and 8-particle scintillation efficiencies (Sa/S8 ~r 50:1). The method of measurement of Sa and S 8 is described. The mechanism of the electronic excitation process is discussed in terms of a plasma resonance of the valence electrons (plasmon creation). The value of is interpreted in terms of’ the decay of the plasmons into the excitation of secondary electrons and the emission of optical phonons. Finally the origin of the large value of s~Js8is shown, from an analysis of the effect of an externally applied electric field upon the values of Sa and S8, to be connected with the magnitude of the self-field produced in the excitation channel (track of the primary particle). The principal spectral component of the scintillation emission (‘blue band’) has been previously identified with the extrinsic recombination of excitons, and the effects produced by an electric field on the particle-induced luminescence are discussed in terms of this hypothesis. (Received 22 ~
1963; in revised form 23 September 1963)
12. THE DEBYE - WAILER FACTORS OF SO~IIJMCHLORIDE. W.J.L. Buyers & T. Smith (Department of Natural Philosophy, University of Aberdeen, Aberdeen, Scotland). The Debye -Waller factors in sodium chloride have been worked out from the normal mode data of Karo and Hardy. It is found that the values for the two ions are almost equal, and considerably ~‘eaterthan recent experimental determinations. The values obtained are determined essentially by the value of the compressibility, but significant changes are found if the deformability of the ions is ignored. Anharmonic contributions to the Debye-Waller factors are discussed. (Received 23 September 1963)
13. THE CO!.~RESSION OF SOZ~RARE EARTH ELEMENTS. D.R. Stephens (university of California, Lawrence Radiation Laboratory, Livermore, California, U.S.A.). The compression (Av/v0) of Pr, Eu, Tb, Yb, and Sc was measured to 45 kbars at room temperature. The phase transformation in Yb reported by several workers was determined to occur at 39.5 ± 0.5 kbar with a volume change of 1.2 ±0.1%. (Received 27 September 1963) 14. SOLID TRANSPORT RATE IN THE VAPOR SOLVENT GROWTH SYSTEM ZnS :1. * F. Jona & G. Mandel (IBM, T.J. Watson Research Center, Yorktown Heights, New York, U.S.A.), Z.~asurements of the rate of’ solid transport have been carried out in the system *
Sponsored in part by the Air Force Office of Scientific Research of the Office of Aerospace Research under Contract PS 49(638)-120l.
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS
245
ber of’ specimens of’ natural diamond, counting technique. reported The limit5a (24.5 using ±1 eV)theis conduction compared with the previously ing minimum value found for value obtained using 8-particle excitation = 18.5 ± 1.5 cv). The observed difference between and is explained quantitatively in terms of the large ratio between the a- and 8-particle scintillation efficiencies (Sa/S8 ~r 50:1). The method of measurement of Sa and S 8 is described. The mechanism of the electronic excitation process is discussed in terms of a plasma resonance of the valence electrons (plasmon creation). The value of is interpreted in terms of’ the decay of the plasmons into the excitation of secondary electrons and the emission of optical phonons. Finally the origin of the large value of s~Js8is shown, from an analysis of the effect of an externally applied electric field upon the values of Sa and S8, to be connected with the magnitude of the self-field produced in the excitation channel (track of the primary particle). The principal spectral component of the scintillation emission (‘blue band’) has been previously identified with the extrinsic recombination of excitons, and the effects produced by an electric field on the particle-induced luminescence are discussed in terms of this hypothesis. (Received 22 ~
1963; in revised form 23 September 1963)
12. THE DEBYE - WAILER FACTORS OF SO~IIJMCHLORIDE. W.J.L. Buyers & T. Smith (Department of Natural Philosophy, University of Aberdeen, Aberdeen, Scotland). The Debye -Waller factors in sodium chloride have been worked out from the normal mode data of Karo and Hardy. It is found that the values for the two ions are almost equal, and considerably ~‘eaterthan recent experimental determinations. The values obtained are determined essentially by the value of the compressibility, but significant changes are found if the deformability of the ions is ignored. Anharmonic contributions to the Debye-Waller factors are discussed. (Received 23 September 1963)
13. THE CO!.~RESSION OF SOZ~RARE EARTH ELEMENTS. D.R. Stephens (university of California, Lawrence Radiation Laboratory, Livermore, California, U.S.A.). The compression (Av/v0) of Pr, Eu, Tb, Yb, and Sc was measured to 45 kbars at room temperature. The phase transformation in Yb reported by several workers was determined to occur at 39.5 ± 0.5 kbar with a volume change of 1.2 ±0.1%. (Received 27 September 1963) 14. SOLID TRANSPORT RATE IN THE VAPOR SOLVENT GROWTH SYSTEM ZnS :1. * F. Jona & G. Mandel (IBM, T.J. Watson Research Center, Yorktown Heights, New York, U.S.A.), Z.~asurements of the rate of’ solid transport have been carried out in the system *
Sponsored in part by the Air Force Office of Scientific Research of the Office of Aerospace Research under Contract PS 49(638)-120l.