scholarly journals Force Constants of the Metaborate Ion in Alkali Halides

1972 ◽  
Vol 56 (10) ◽  
pp. 5189-5190 ◽  
Author(s):  
J. C. Decius ◽  
C. R. Becker ◽  
W. J. Fredericks
Keyword(s):  
Alkali Halides ◽  
Force Constants

scholarly journals Erratum: Force constants of the metaborate ion in alkali halides

1973 ◽  
Vol 58 (4) ◽  
pp. 1782-1782
Author(s):  
J. C. Decius ◽  
C. R. Becker ◽  
W. J. Fredericks
Keyword(s):  
Alkali Halides ◽  
Force Constants

Lattice relaxation around impurity pairs in alkali halides

1976 ◽  
Vol 54 (19) ◽  
pp. 2010-2017
Author(s):  
T. L. Templeton ◽  
B. P. Clayman
Keyword(s):  
Nearest Neighbor ◽  
Molecular Model ◽  
Linear Chain ◽  
Alkali Halides ◽  
Lattice Relaxation ◽  
Resonant Absorption ◽  
Force Constants ◽  
Chain Model ◽  
Absorption Frequencies ◽  
Good Agreement

The rigid ion model is applied to the calculation of the relaxation of the lattice around single impurities and pairs of impurities in alkali halide host-defect systems. The calculated relaxation of nearest neighbors is typically a few percent of the host crystal lattice constant. Relaxation falls off with increasing distance from the defects. Nearest neighbor force constants derived from this calculation are, in some cases, in good agreement with those obtained by fitting the resonant absorption frequencies of the vibrational modes of these impurity centres to a molecular model. In other cases the extreme anisotropy of the relaxed force constants is seen to prevent the application of a simple molecular model. The calculated force constants, when used in a linear chain model, give good qualitative agreement with experiment.

Lattice relaxation around tetragonal and rhombic defects in alkali halides

1979 ◽  
Vol 57 (8) ◽  
pp. 1209-1215
Author(s):  
B. P. Clayman
Keyword(s):  
Nearest Neighbor ◽  
Alkali Halides ◽  
Nearest Neighbors ◽  
Lattice Relaxation ◽  
Force Constants ◽  
Tetragonal Symmetry ◽  
Model Calculations ◽  
Host Interactions ◽  
Rhombic Symmetry ◽  
Rigid Ion Model

The relaxation of the crystal lattice around impurity pair defects in alkali halides is calculated based on a rigid ion model. Pairs with tetragonal symmetry—fourth nearest neighbors along the [001] axis—and those with rhombic symmetry—second nearest neighbors along the [110] axis— are both considered, for all cases where experimental evidence exists for resonant or gap modes. These are: NaCl with F−, Li+, and Ag+; KI with Cl−, Br−, Na+, and Rb+; KCl with Na+; and NaBr with Li+. Relaxation spaces with 72 ions (tetragonal) and 50 ions (rhombic) are used and results reported for all ions within the spaces. The nearest neighbor central force constants coupling the impurity ions and their nearest neighbors are calculated in the rigid ion approximation and the results compared with earlier dynamical model calculations. Because the dynamical models assumed that only one perturbed force constant was needed to characterize all the impurity–host interactions, and significant directional inhomogeneity of the force constants was a result of the present calculations, only qualitative comparisions could be made.

Force constants and chemical hardnesses

1997 ◽  
Vol 92 (3) ◽  
pp. 353-358 ◽  
Author(s):  
S. ARULMOZHIRAJA ◽  
P. KOLANDAIVEL
Keyword(s):  
Force Constants

DIFFUSION AND MOBILITY IN ALKALI HALIDES IN THE EXTRINSIC REGION

1973 ◽  
Vol 34 (C9) ◽  
pp. C9-425-C9-430 ◽  
Author(s):  
L. B. HARRIS ◽  
J. L. SCHLEDERER
Keyword(s):  
Alkali Halides

A THEORETICAL STUDY OF INTRINSIC AND EXTRINSIC DEFECT PROPERTIES OF ALKALI HALIDES

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-253-C7-259 ◽  
Author(s):  
C. R.A. CATLOW ◽  
J. CORISH ◽  
K. M. DILLER ◽  
P. W.M. JACOBS ◽  
M. J. NORGETT
Keyword(s):  
Theoretical Study ◽  
Alkali Halides ◽  
Extrinsic Defect

ELECTROLYTIC COLORATION IN ALKALI HALIDES. ROLE OF THE SPACE CHARGE ON THE COLOR PROPAGATION

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-86-C7-86
Author(s):  
M. T. MONTOJO ◽  
F. JAQUE ◽  
C. SÁNCHEZ
Keyword(s):  
Space Charge ◽  
Alkali Halides

Dopant aggregation and precipitation in alkali halides doped with divalent ions

1980 ◽  
Vol 41 (C6) ◽  
pp. C6-68-C6-71 ◽  
Author(s):  
J. Corish ◽  
J. M. Quigley ◽  
C. R. A. Catlow ◽  
P. W.M. Jacobs
Keyword(s):  
Alkali Halides ◽  
Divalent Ions
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