Stability of Crystals of Rare-Gas Atoms and Alkali Halides in Terms of Three-Body Interactions. II. Alkali-Halide Crystals

1964 ◽  
Vol 136 (4A) ◽  
pp. A1011-A1023 ◽  
Author(s):  
Erminio Lombardi ◽  
Laurens Jansen
1974 ◽  
Vol 29 (11) ◽  
pp. 1601-1607
Author(s):  
K. D. Misra ◽  
V. K. Dixit ◽  
M. N. Sharma

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.


Optics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 18-31 ◽  
Author(s):  
Khagendra P. Bhandari

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.


1975 ◽  
Vol 53 (2) ◽  
pp. 192-199 ◽  
Author(s):  
Taiju Tsuboi ◽  
K. Oyama ◽  
P. W. M. Jacobs

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.


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