Accumulation of F centers in alkali-halide crystals at room temperature

1975 ◽  
Vol 18 (8) ◽  
pp. 1102-1105
Author(s):  
N. S. Kravchenko
Keyword(s):  
Alkali Halide ◽  
Room Temperature ◽  
Alkali Halide Crystals ◽  
F Centers

On the Anderson Transition in Electronic Color Centers Systems in Alkali Halide Crystals

1982 ◽  
Vol 37 (6) ◽  
pp. 613-614
Author(s):  
A. A. Berezin
Keyword(s):  
Alkali Halide ◽  
Random Potential ◽  
High Concentration ◽  
Potential Fluctuations ◽  
Anderson Transition ◽  
Anion Vacancies ◽  
Alkali Halide Crystals ◽  
Localization Condition ◽  
Positively Charged ◽  
F Centers

Abstract An alkali halide crystal with a high concentration of F-centers is considered. If some of these F-centers are ionized into anion vacancies (a-centers) released electrons can be trapped by other F-centers to form F′-centers. It is shown that for each original concentration of F-centers there is a certain concentration of F′-centers for which the random potential fluctuations due to negatively charged F′-centers and positively charged a-centers have enough amplitude to create Anderson localization condition in the system of F-, F′- and a-centers.

Optical Absorption Spectra of KBr:Pb2+ Crystals

1973 ◽  
Vol 51 (21) ◽  
pp. 2242-2248 ◽  
Author(s):  
Robert E. Chaney ◽  
P. W. M. Jacobs ◽  
Taiju Tsuboi
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Alkali Halide ◽  
Room Temperature ◽  
Nonlinear Least Squares ◽  
Energy Separation ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Fundamental Properties ◽  
Alkali Halide Crystals

The fundamental properties of the absorption spectra of KBr:Pb2+ crystals have been studied at various temperatures from the liquid helium range to room temperature. The observed absorption bands are assigned to the so-called A, B, C, and D' bands by analogy with the absorption bands of other s2-configuration ions in alkali halide crystals. The B, C, and D′ bands overlap but have been resolved into their components by nonlinear least squares analysis. A discussion is given of the energy separation between the B and C bands in Sn2+-, Tl+-, and Pb2+-doped alkali halide crystals.

Electron Microscopy of Precipitates of NaCl: FeCl2 Crystals

1977 ◽  
Vol 35 ◽  
pp. 258-259
Author(s):  
M. Jose Yacaman ◽  
R. W. Vook
Keyword(s):  
Electron Microscopy ◽  
Atomic Absorption Spectroscopy ◽  
Alkali Halide ◽  
Impurity Concentration ◽  
Room Temperature ◽  
Volume Fraction ◽  
Nucleation Density ◽  
Controlled Atmosphere ◽  
Alkali Halide Crystals ◽  
Kyropoulos Method

Suzuki phase precipitates1 produced by divalent impurities in alkali halide crystals can act as preferential gucleation sites for vapor deposited metals using the gold decoration method2. The present work applies this technique to the study of NaCl: FeCl2. Crystals with several FeCl2 concentrations were grown by the Kyropoulos method in a controlled atmosphere and thermally homogenized. The final impurity concentration Cs was determined by atomic absorption spectroscopy. Precipitates were inducel bg linear cooling from 550°C to room temperature at rates of 7.64, 3.82, and 23°C/hr. Gold decoration was performed at 10 Torr on vacuum-cleaved surfaces at 100°C. Precipitates were visible because of an enhanced nucleation density: Figs. la - c. The volume fraction Vσ of precipitates was determined from the total fractional area of the precipitates in micrographs taken from several areas of the replicas. Vσ is linearly related to Cs (Fig. 2) with a slope of 8.1 ± 1.0.

Photoacoustic Signals from F Centers in Alkali Halide Crystals

1984 ◽  
Vol 53 (5) ◽  
pp. 1621-1623 ◽  
Author(s):  
Katsuyuki Inabe ◽  
Shoichi Nakamura ◽  
Nozomu Takeuchi
Keyword(s):  
Alkali Halide ◽  
Alkali Halide Crystals ◽  
F Centers

On the nature of spontaneous rupture of F centers in alkali-halide crystals

1975 ◽  
Vol 18 (4) ◽  
pp. 541-542
Author(s):  
Yu. M. Annenkov ◽  
V. F. Pichugin ◽  
T. S. Frangul'yan
Keyword(s):  
Alkali Halide ◽  
Spontaneous Rupture ◽  
Alkali Halide Crystals ◽  
F Centers
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