Vol 17.No 7 ABSTRACTS OF PAPERS TO APPEAR IN J PHYS CHEM. SOLIDS V

*

8 ISOTOPE EFFECTS IN RAMAN SPECTRA OF CRYSTALLINE ALKALI-METAL CHLORATES AND BROMATES

J B. Bates and H.D Stldham, Sohd State DIMsion, Oak hdge National Laboratory, Oak &dge, TN 37830, U.S A

Halogen and oxygen atom Isotope effects have been observed m Raman spectra of smgle crystal NaC103, KCIOJ, NaBrOB, and KBr03 Onentatlonal sphttmg of 35Cl ‘602 lsO- ion vlbratlonal modes was observed m KC103 Sphttmg of the v1 mode of %r and ” Br isotopes of smgly substituted “0 and ‘80 bromate ions 111 NaBr03 and KBr031s on the order of 1 5 cm-’ m agreement with a calculation of isotopic frequencies However, the predicted sphttmg between vl of the major isotopes, 79Br160; and 81Br’60;, was not observed, and the results of a band contour analysis suggest that a smgle k = 0 phonon 1s denved from the totally symmetnc stretchmg mode of both species

Recewed 24 Apnll975

9 ELECTRONIC POLARIZABILITIES AND SIZED OF IONS IN ANBleN TYPE SEMI- CONDUCTORS

Jai Shanker and S K Agarwal, Department of Physics, Agra College, Agra-282002, In&a.

Electronic polanzabtitles and sizes of ions m ANBleN type semiconductors (PbS, PbSe, PbTe and SnTe) have been deduced m the present study The free ion polarizabtities of Sn2+ and Pb2* ions are esti- mated approxtmately followmg the procedure of Pauhng The effect of crystalhne potential is then estunated on free cation polanzabhtles An empmcal relation between loruc radu and polanzabllrtles has been apphed to deduce the ~omc sizes and amon polanzabtitles The calculated molecular electromc polamablimes agree well with the expenmental values The vatlatlon of dielectric constant wth stram has also been estunated 111 each crystal and the results are explamed m terms of the optical amsotropy para- meter

Recewed 10 December 1974 Rewed 5 May 1975

10 RESONANT BRILLOUIN SCATTERING BY ACOUSTOELECTRICALLY AMPLI- FIED PHONONS IN CdSe

K Yamamoto, K Mlsawa, H Shlmlzu and K Abe, Department of Electronic Engneer- mg, Kobe Uruverslty, Rokko, Nada, Kobe, Japan

The dispersion of Bnlloum scattering efficiency from the acoustoelectrlcally amplified phonon flux m CdSe has been measured m the range 1 37-l 65 eV The dispersion curve shows enhancement and cancel- lation slmdar to those of GaAs, CdS and ZnO, and 1s m a good agreement with molfied Loudon theory mcludmg exclton effects

Recerved 21 Apnl 1975

11 ELECTRON AND HOLE CONDUCTIVITY l IN CuInS2

D C Look and J.C Manthuruthll, Phystcs Department, University of Dayton, Dayton, OH 45469, U S A

Single crystals of CuInS2 have been grown from the melt and annealed m In or S to produce good n- or p-type conductlvlty, respectively, Two donor levels, one shallow and one deep (0 35 eV), and one acceptor level at 0 15 eV are identified. The hole-mobdity data are best fitted with an effective mass rn3: = 1 3 m,, which can be explamed by simple, two band k-p theory if the valence band has appreciable d character Above 300”K, the hole mobhty falls rapidly, evl- dently due to multxband conduction and/or mterband scattenng between the nondegenerate and degenerate valence bands The conduction band moblhty appears to be dommated, m many samples, by large concen- trations (> 1018 cm-‘) of native donors and acceptors, which are closely compensated

Recerved 11 June 1975

12 A STATISTICAL MECHANICAL MODEL FOR SOLID SOLUTIONS OF HYDROGEN IN THE METALS NIOBIUM, VANADIUM AND TANTALUM

Rex B McLellan, Department of Mechanical