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Note on the first order Raman spectrum of CuCl

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HAL Id: jpa-00206046

https://hal.archives-ouvertes.fr/jpa-00206046

Submitted on 1 Jan 1965

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Note on the first order Raman spectrum of CuCl

S. Iwasa, E. Burstein

To cite this version:

S. Iwasa, E. Burstein. Note on the first order Raman spectrum of CuCl. Journal de Physique, 1965,

26 (11), pp.614-614. �10.1051/jphys:019650026011061400�. �jpa-00206046�

(2)

614.

NOTE ON THE FIRST ORDER RAMAN SPECTRUM OF CuCl (1)

By S. IWASA and E. BURSTEIN,

Laboratory for Research

on

the Structure of Matter and Physics Department, University of Pennsylvania, Philadelphia, Pennsylvania, U. S. A.

Résumé.

2014

Observation du spectre Raman de monocristaux. Comparaison avec les résultats antérieurs.

Abstract.

2014

The Raman spectrum of single crystals is griven and the results compared with

those of previous experiments.

LE JOURNAL DE

PHYSIQUE

TOME

26,

NOVEMBRE

1965,

We have carried out preliminary photographic

measurements of the first order Raman spectrum

of Cu Cl at room temperature using a 10 milli-

watt He-Ne laser as the source of the exciting

radiation and a medium quartz Hilger spectro- graph. The room temperature spectra which we

have obtained closely resemble the spectra for

zincblende obtained by Couture-Mathieu and Mathieu [1] in 1953. Thus, for the case where the

incident and scattered radiation were both pola-

rized in the plane of scattering, the intensity of

the LO line is appreciably greater than that of

the T D line. Our results which are still tentative

yield wr,

=

201 cm-1 and cor

=

153 cm-1.

These values for the LO and T 0 frequencies are in good agreement with the corresponding values,

wL

=

195 cm-1 and cor

=

155 em-1 derived from

oblique incidence tranrmission measurement on

thin epitaxial films [2]. The infrared measure-

ments indicate a dependence of COL on mechanical strain, which may account for part of the diffe-

rence in the measured values.

Our results for the fundamental optical vibra-

tion frequencies are at variance with those obtained (1) Research supported by the U. S. Office of Naval Research and the U. S. Army Research Office, Durham.

by other investigators. Thus, Henninger, Morlot,

and Hadni [3] report cor

=

172 cm-1 based on

normal incidence transmission measurements on

thin films, and Mathieu, Poulet, and Tramer [4]

report (ÙL

=

290 cm-1 based on Raman scattering

measurements on compressed powders for which only one line was observed. Application of the Lyddane-Sachs-Teller relation to our infrared re- sults, namely SS/Co

-

C02 L /W2 T - 1.52 with

E:o

=

4.8 [5], yields es

=

7.4, in good agreement

with the value (ES

=

7.5) obtained at C-band fre- quencies [6]. This value for the static dielectric constant is appreciably smaller than the one

(as

--

10) reported in the literature [7], which has

been used to calculate (ÙL from COT. By combi- ning the values for so, COT, and (ÙL we obtain e* = 0 . 51 e for the Szigeti effective charge and e*

=

1.15 e for the Born effective charge, which

are appreciably lower than the values derived from the earlier values of es and COT [7].

We wish to acknowledge the advice of

T. E. Walsh of the RCA Laboratories, Princeton,

N. J. regarding the preparation of single crystals

of CuCI and the valuable assistance of Mr. Peter Parkinson of the Physics Department in setting up the Raman experiments.

REFERENCES [1] COUTURE-MATHIEU (L.) and MATHIEU (J. P.), C. R.

Acad. Sc., 1953, 236, 371.

[2] IWASA (S.) and BURSTEIN (E.), Bull. Am. Phys. Soc., 1963, Ser. 11, 10, No. 3.

[3] HENNINGER (Y.), MORLOT (G.) and HADNI (A.), J. Phy- sique, 1965, 26, 193.

[4] MATHIEU (J. P.), POULET (H.) and TRAMER (A.), Z. Elec-

trochem., 1960, 64, 699.

[5] REISS (R.), Cahiers Phys., 1959, 13, 129.

[6] STERZER (F.), BLATTNER (D.) and MINITER (S.), J. Opt.

Soc. Amer., 1964, 54, 62.

[7] BORN (M.) and HUANG (K.), Dynamical Theory of Crystal Lattices, 1954 (Oxford : Clarendon Press).

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:019650026011061400

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