An Exponential Function for Repulsive Interaction Energy Term I. Application to Alkali Halides

1974 ◽  
Vol 29 (11) ◽  
pp. 1601-1607
Author(s):  
K. D. Misra ◽  
V. K. Dixit ◽  
M. N. Sharma
Keyword(s):  
Equation Of State ◽  
Alkali Halide ◽  
Alkali Halides ◽  
Good Choice ◽  
Repulsive Interaction ◽  
Energy Term ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
Alkali Halide Crystals ◽  
Potential Parameters

The appropriateness of a suitably modified Varshni-Shukla potential has been tested for a series of alkali halide crystals by determining the numerical values of the potential parameters involved, using Hildebrand’s equation of state and thereby computing a few lattice properties. Comparison between the different sets of theoretical and experimental results infers that the present theoretical values exhibit an improvement over those of other workers, using a similar approach but with different potential energy functions. It is concluded that the modified V -S potential function is a good choice for explaining the behaviour of alkali halide lattices.

scholarly journals Optical Properties of Alkali Halides in Ultraviolet Spectral Regions

Optics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 18-31 ◽  
Author(s):  
Khagendra P. Bhandari
Keyword(s):  
Alkali Halide ◽  
Optical Constants ◽  
Complex Function ◽  
Alkali Halides ◽  
Current Theory ◽  
Dielectric Constants ◽  
The Real ◽  
Band Transition ◽  
Alkali Halide Crystals ◽  
Kronig Relation

The optical reflectance spectra of alkali halide crystals KI and RbI were measured over the energy range of 4.14 to 6.91 eV. Both single crystal and poly-crystal samples were used to accomplish this task. The phase θ ( ω ) was computed using the Kramers-Kronig relation between the real and imaginary parts of the complex function, ln r = ln | r | + i θ ( ω ) . Subsequently, the optical constants n and κ were determined from the Fresnel reflectivity equation. The real and imaginary parts of dielectric constants ε 1 and ε 2 were then calculated using n and κ. The optical absorption spectra of the crystal have also been measured in these spectral regions. The spectra agree reasonably well with the current theory concerning exciton peaks. In addition, a shoulder was found in the spectra similar to those previously seen and associated with the band-to-band transition in the alkali iodides.

Line Shape of the A Band of s2 Configuration Ions in Alkali Halide Crystals

1975 ◽  
Vol 53 (2) ◽  
pp. 192-199 ◽  
Author(s):  
Taiju Tsuboi ◽  
K. Oyama ◽  
P. W. M. Jacobs
Keyword(s):  
Fine Structure ◽  
Line Shape ◽  
Alkali Halide ◽  
Alkali Halides ◽  
Systematic Investigation ◽  
Temperature Sensitive ◽  
Doublet Structure ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Alkali Halide Crystals

A systematic investigation of the line shape of the A band of several ions with the s2 configuration dissolved in alkali halides has been made on KCl:In+, KBr:In+, KCl:Sn2+, KBr:Sn2+, KI:Sn2+, RbCl:Sn2+, KCl:Tl+, KBr:Tl+, KI:Tl+, and KBr:Pb2+ crystals. A temperature sensitive doublet structure was observed for In+ and Sn2+ doped crystals and for KCl:Tl+, while a single band, which is asymmetric at high temperatures, was observed for KBr:Tl+ and KBr:Pb2+. The temperature dependence of the line shape supports Toyozawa and Inoue's theory in which the fine structure is ascribed to the dynamical Jahn–Teller effect. A discussion is given of the importance of quadratic electron–lattice interaction and its effect on the asymmetry of the line shape.

Empirical interionic potentials for alkali halide molecules

1984 ◽  
Vol 62 (6) ◽  
pp. 583-589 ◽  
Author(s):  
J. E. Szymanski ◽  
J. A. D. Matthew
Keyword(s):  
Binding Energy ◽  
Alkali Halide ◽  
Energy Functions ◽  
Gaussian Form ◽  
Potential Energy Functions ◽  
Dissociation Energies ◽  
Anharmonic Constant ◽  
Empirical Potentials ◽  
Repulsion Potential ◽  
Extreme Care

A systematic study of families of empirical internuclear potential energy functions based on the Rittner potential is presented for alkali halide molecules, and comparison is made with recent binding energy and anharmonic constant data. It is concluded that the Rittner formalism, however parameterized, is incapable of consistent prediction of several molecular properties simultaneously, and that the potential seems to be failing to model some aspect of the detailed bonding of the molecule. Inclusion of a Gaussian form of repulsion potential in the model gives excellent agreement for the dissociation energies, but in general extreme care must be taken when applying empirical potentials of the Rittner form to more complex systems such as ionized molecules or clusters.

An equation of state for alkali halide crystals

1976 ◽  
Vol 19 (1) ◽  
pp. 81-84 ◽  
Author(s):  
V. A. Zhdanov ◽  
V. V. Polyakov
Keyword(s):  
Equation Of State ◽  
Alkali Halide ◽  
Alkali Halide Crystals

Transverse quadratic electrostrictive effect in alkali halides with the NaCl structure*

1986 ◽  
Vol 176 (3-4) ◽  
Author(s):  
W. Kucharczyk
Keyword(s):  
Simple Model ◽  
Alkali Halide ◽  
Alkali Halides ◽  
Relative Displacement ◽  
Longitudinal Deformation ◽  
Positive Ions ◽  
Alkali Halide Crystals ◽  
Electrostrictive Effect

AbstractA simple model of the quadratic transverse electrostrictive effect in alkali halide crystals with the NaCl structure is considered. Two contributions to the transverse coefficient are taken into account. The first term is due to the relative displacement of the negative and positive ions. The second one is related to the coupling of transverse and longitudinal deformation.

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