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17. The diffuse reflectance spectra of some titanium oxides
Vol. i, No. 1
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CH~4. SOLIDS
19
by an e l e c t r i c a l p o t e n t i a l d i f f e r e n c e ~ independent o f ~ t ) d e v e l o p e d a c r o s s t h e f i l m . The p a r a m e t e r s ~ and ~ depend on r e l a t i v e v a l u e s o f t h e p r o d u c t s o f c o n c e n t r a t i o n C and m o b i l i t y ~ , i n c r e a s i n g w i t h i n c r e a s i n g ~ C f o r t h e electro¢,~c s p e c i e s and d e c r e a s i n k w i t h i n c r e a s i n g ~C f o r t h e i o n i c s p e c i e s . T y p i c a l v a l u e s o f g , - ~ ~ a r e 0.3 Y and 3. F o r e q u a l v a l u e s of ~C, ~ i s n e a r l y z e r o and S i s a p p r o x i m a t e l y ~ in the space chcTge l i m i t . N o n - n e K l i g i b l e space charge r e l a t i v e t o i n t e r r a c i a l charge d e n s i t y decreases ~ . In certain cases, ~ and .~ depend on ~ t ) , so departures from pazabollc o c c u r , e s p e c i a l l y i n t h e t r a n s i e n t stages of growth. Nmaerical s o l u t i o n s f o r constant e x t e r , ~ 1 o r s u r f a c e o r charge fields yield Nth root ,,~ logarit2~alc ]AWl. S l i c e charge can a i d o r h i n d e r growth; t h i s i s d e t e r m i n e d by t h e c o n t r i b u t i o n o f t h e space charge f i e l d t o t r a n s p o r t and t h e change i n i o n d i s t r i b u t i o n f o r t h i s f i e l d . Expe~imenT~Ll d~ta for growth of Cu20 on Cu el-ystals at 50 and lO0°C were fit a s s u ~ - - - 1 1 space charge. ( R e c e i v e d 20 August 1962; i n r e v i s e d form 25 MarCh 1963) 15. THE OPTICAL ~ C T I V E MASS AND ABSORPTION EDGE OF ELECTRCUS IN S O n i C . J.N. H~xlgson (Physics Dept., The University, Keels, Staffordshire, ~ - ~ - ~ . ) The optical constants of so~ium have been measured by a reflection method in the wavelength range 0.65-2.5 x i0"~ ca. The values of dielectric constant in the infrared give an optical effective :~ss m~ -- (1.08 ~ O.Ol)m. The variation of conductivity with wavelength indicates the onset of inter-band transitions at a photon energy of 1.2 eV. A comparison with the theoretical band structure suggests that t h e s e may be indirect transitions from t h e Fermi surface. (Received 29 March 1963)
16. ~
AWD D Z S ~ U E P ~
PROCESSES IN Cu3Au. III.
L.R. Weisberg & S.L. Qulmb~Colun~ia University, New York 27, New York, U.S.A.) The i s ~ change of Young's modulus with time is measured in a sin61e crystal of C~3Au following a s-aden change in temperature above and through the critical temperature, Tc, when the specimen is initially in one of the various states of long and short ~ order. Short range ordering changes above and close to T are found to be co~plete~ within minutes. Evidence is adduced for the existence of c a metastable short range order below T . When the specimen is quenched from above T c to below, it is show~ that ~ contin.~l Uformation of new ordered nuclei is an important part of the o r d e r i n ~ process. Equations are presented exPlalnlng t h e principal features of t h e ordering curves in % ~ of the relative contributions of nucleus formation ,~4 growth. When the specimen is heated from below T_ to above, it is deduced that the disorder diff~s i~ each ~ n b o ~ into theUdo~alns. Also, the initial disordering ~ate ilaed/a~ely above T c is controlled by the existence of a metastable state of long range order. (Received 3 April 1963) 17. ~ E DIFFUSE REFLECTANCE SPECTRA ~F SOME TITANIIq4 OXIDES. A.L. C~q~ulion & R.E. Wyatt (Dept. of Chemistry, Illinois Institute of Technology, Chicago 16, T114nois, U.S.A.) Diffuse reflectance spectra in t h e visible and near ultraviolet are reported for TiO, Ti20~, and the an~tase, f u t i l e and n a t u r a l b r o o k i t e crystalline modifications of TiO~. ResUlts are interpreted qualitatively in the light of crystal field theory. (Received 3 April 1963) 18. TH~RP~L EXPARSIC~ OF SILVER IODIDE. A. Bienenstock & G. Burley (National Bureau of Standards, Washington 25, D.C., U.S.A.)
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CH~4. SOLIDS
19
by an e l e c t r i c a l p o t e n t i a l d i f f e r e n c e ~ independent o f ~ t ) d e v e l o p e d a c r o s s t h e f i l m . The p a r a m e t e r s ~ and ~ depend on r e l a t i v e v a l u e s o f t h e p r o d u c t s o f c o n c e n t r a t i o n C and m o b i l i t y ~ , i n c r e a s i n g w i t h i n c r e a s i n g ~ C f o r t h e electro¢,~c s p e c i e s and d e c r e a s i n k w i t h i n c r e a s i n g ~C f o r t h e i o n i c s p e c i e s . T y p i c a l v a l u e s o f g , - ~ ~ a r e 0.3 Y and 3. F o r e q u a l v a l u e s of ~C, ~ i s n e a r l y z e r o and S i s a p p r o x i m a t e l y ~ in the space chcTge l i m i t . N o n - n e K l i g i b l e space charge r e l a t i v e t o i n t e r r a c i a l charge d e n s i t y decreases ~ . In certain cases, ~ and .~ depend on ~ t ) , so departures from pazabollc o c c u r , e s p e c i a l l y i n t h e t r a n s i e n t stages of growth. Nmaerical s o l u t i o n s f o r constant e x t e r , ~ 1 o r s u r f a c e o r charge fields yield Nth root ,,~ logarit2~alc ]AWl. S l i c e charge can a i d o r h i n d e r growth; t h i s i s d e t e r m i n e d by t h e c o n t r i b u t i o n o f t h e space charge f i e l d t o t r a n s p o r t and t h e change i n i o n d i s t r i b u t i o n f o r t h i s f i e l d . Expe~imenT~Ll d~ta for growth of Cu20 on Cu el-ystals at 50 and lO0°C were fit a s s u ~ - - - 1 1 space charge. ( R e c e i v e d 20 August 1962; i n r e v i s e d form 25 MarCh 1963) 15. THE OPTICAL ~ C T I V E MASS AND ABSORPTION EDGE OF ELECTRCUS IN S O n i C . J.N. H~xlgson (Physics Dept., The University, Keels, Staffordshire, ~ - ~ - ~ . ) The optical constants of so~ium have been measured by a reflection method in the wavelength range 0.65-2.5 x i0"~ ca. The values of dielectric constant in the infrared give an optical effective :~ss m~ -- (1.08 ~ O.Ol)m. The variation of conductivity with wavelength indicates the onset of inter-band transitions at a photon energy of 1.2 eV. A comparison with the theoretical band structure suggests that t h e s e may be indirect transitions from t h e Fermi surface. (Received 29 March 1963)
16. ~
AWD D Z S ~ U E P ~
PROCESSES IN Cu3Au. III.
L.R. Weisberg & S.L. Qulmb~Colun~ia University, New York 27, New York, U.S.A.) The i s ~ change of Young's modulus with time is measured in a sin61e crystal of C~3Au following a s-aden change in temperature above and through the critical temperature, Tc, when the specimen is initially in one of the various states of long and short ~ order. Short range ordering changes above and close to T are found to be co~plete~ within minutes. Evidence is adduced for the existence of c a metastable short range order below T . When the specimen is quenched from above T c to below, it is show~ that ~ contin.~l Uformation of new ordered nuclei is an important part of the o r d e r i n ~ process. Equations are presented exPlalnlng t h e principal features of t h e ordering curves in % ~ of the relative contributions of nucleus formation ,~4 growth. When the specimen is heated from below T_ to above, it is deduced that the disorder diff~s i~ each ~ n b o ~ into theUdo~alns. Also, the initial disordering ~ate ilaed/a~ely above T c is controlled by the existence of a metastable state of long range order. (Received 3 April 1963) 17. ~ E DIFFUSE REFLECTANCE SPECTRA ~F SOME TITANIIq4 OXIDES. A.L. C~q~ulion & R.E. Wyatt (Dept. of Chemistry, Illinois Institute of Technology, Chicago 16, T114nois, U.S.A.) Diffuse reflectance spectra in t h e visible and near ultraviolet are reported for TiO, Ti20~, and the an~tase, f u t i l e and n a t u r a l b r o o k i t e crystalline modifications of TiO~. ResUlts are interpreted qualitatively in the light of crystal field theory. (Received 3 April 1963) 18. TH~RP~L EXPARSIC~ OF SILVER IODIDE. A. Bienenstock & G. Burley (National Bureau of Standards, Washington 25, D.C., U.S.A.)