- Email: [email protected]
The elastic constants of cadmium sulfide between 4.2–300°K
Solid State Communications, Vol. 5, pp. i -viii, 1967. Pergamon Press Ltd. Printed in Great Britain
Abstracts of Articles to be Published in the Journal of the Physics and Chemistry of Solids “J. Phys. Chem. Solids (to be published)” should be cited in references to material quoted from this section prior to the publication of the relevant article.
1.
VAPOR PRESSURES AND PHASE EQUILIBRIA IN THE Ga-As SYSTEM J. R. Arthur (Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey)
Mass spectrometric and weight loss measurements of the species effusing from a Knudsen cell containing GaAs were used to obtain vapor pressures over the temperature range 900-1200°K. The As2 /As4 ratio was observed in these measurements to be substantially larger than previously reported when precautions were taken to prevent the buildup of arsenic vapor in the mass spectrometer ionization chamber. A third law treatment of the data gave enthalpies for the reactions: GaAs ~
—
Ga
+
GaAs ~
—
Ga ~
2As2 ~
—
As4
GaAs
—
Ga
+
~As2 ,~ AH~= 44. 9 kcal +As4 ~
AH~= 29. 4 kcal
(Received 16 September 1965) (Revised 12 April 1967) 3.
REGLES DE SELECTION POUR DES PROCESSUS INFRAROUGE ET RAMAN DU DEUXIEME ORDRE DANS LE F2Mg Claude Benoit (Département de Physique Cristalline, Faculté des Sciences, Montpellier, France)
AH~= -62. 5kcal
(g)
+
As,~
AH~= 155 kcal
These results were used to correct Thurmond’s calculations of vapor pressures and activity coefficients along the GaAs liquidus. (Received 9 March 1967) (Revised 18 May 1967) 2.
the temperature range 4. 2-300°K. They were calculated from measurements of the sound velocity in different crystalline directions by the pulse superposition method. All elastic constants increase with decreasing temperature, the variation being somewhat larger for the cross coupling constants than for the diagonal ones. From the low temperature values of the elastic constant, the Debye temperature at O°Kfor CdS is determined as 219. 3°K.
THE ELASTIC CONSTANTS OF CADMIUM SULFIDE BETWEEN 4. 2-300°K D. Gerlich (RCA Laboratories, Princeton, N.J.)
The five independent elastic constants of single crystal CdS have been determined over
On obtient pour des points particuliers de la zone Brillouin, les caractères des représentations irréductibles du groupe spatial cornplet. On déduit les règles de selection pour des processus a deux phonons dans l’infrarouge etla diffusion Raman pour des cristaux ayant la structure du rutile. The characters of irreductible representations of full space group are given for some points of first Brillouin zone. Group theoretical selection rules are determined for two phonons infrared absorption and Raman scattering processes in crystals having the rutile structure. (Received 6 March 1967)
Abstracts of Articles to be Published in the Journal of the Physics and Chemistry of Solids “J. Phys. Chem. Solids (to be published)” should be cited in references to material quoted from this section prior to the publication of the relevant article.
1.
VAPOR PRESSURES AND PHASE EQUILIBRIA IN THE Ga-As SYSTEM J. R. Arthur (Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey)
Mass spectrometric and weight loss measurements of the species effusing from a Knudsen cell containing GaAs were used to obtain vapor pressures over the temperature range 900-1200°K. The As2 /As4 ratio was observed in these measurements to be substantially larger than previously reported when precautions were taken to prevent the buildup of arsenic vapor in the mass spectrometer ionization chamber. A third law treatment of the data gave enthalpies for the reactions: GaAs ~
—
Ga
+
GaAs ~
—
Ga ~
2As2 ~
—
As4
GaAs
—
Ga
+
~As2 ,~ AH~= 44. 9 kcal +As4 ~
AH~= 29. 4 kcal
(Received 16 September 1965) (Revised 12 April 1967) 3.
REGLES DE SELECTION POUR DES PROCESSUS INFRAROUGE ET RAMAN DU DEUXIEME ORDRE DANS LE F2Mg Claude Benoit (Département de Physique Cristalline, Faculté des Sciences, Montpellier, France)
AH~= -62. 5kcal
(g)
+
As,~
AH~= 155 kcal
These results were used to correct Thurmond’s calculations of vapor pressures and activity coefficients along the GaAs liquidus. (Received 9 March 1967) (Revised 18 May 1967) 2.
the temperature range 4. 2-300°K. They were calculated from measurements of the sound velocity in different crystalline directions by the pulse superposition method. All elastic constants increase with decreasing temperature, the variation being somewhat larger for the cross coupling constants than for the diagonal ones. From the low temperature values of the elastic constant, the Debye temperature at O°Kfor CdS is determined as 219. 3°K.
THE ELASTIC CONSTANTS OF CADMIUM SULFIDE BETWEEN 4. 2-300°K D. Gerlich (RCA Laboratories, Princeton, N.J.)
The five independent elastic constants of single crystal CdS have been determined over
On obtient pour des points particuliers de la zone Brillouin, les caractères des représentations irréductibles du groupe spatial cornplet. On déduit les règles de selection pour des processus a deux phonons dans l’infrarouge etla diffusion Raman pour des cristaux ayant la structure du rutile. The characters of irreductible representations of full space group are given for some points of first Brillouin zone. Group theoretical selection rules are determined for two phonons infrared absorption and Raman scattering processes in crystals having the rutile structure. (Received 6 March 1967)