The absorption spectrum of polycrystalline silver halide fibres

The wavelength dependence of the attenuation in polycrystalline AgCl:AgBr fibre has been determined between 2.5 μm and 14 μm. The background attenuation as λ^-2 dependence as expected but there are also strong absorption peaks due to water and silver oxide which, to our knowledge, are observed for the first time in these fibres.     

The far-infrared absorption spectra of some alkali halide alloys

A study has been made of the far-infrared transmission spectra of some K_xRb_1−x⁻ Cl_yBr1−y alloys with (x,y) ≈ 1 mole%. and the results are reported in this paper. An absorption band at 94.5cm⁻¹ in KBr:Cl has been observed, in agreement with the results of other workers. New bands at 99 cm⁻¹ in KBr:Rb. 99 cm⁻¹ in RbCl:K and 103 cm⁻¹ in RbCl:Br have also been found. These bands are attributed to impurity-induced modes in the gaps in the frequency distributions of KBr and RbCl. Comparison of these results with the theoretical results of Mitani and Takeno indicates that the ‘force constants’ associated with Rb and Br impurities are enhanced relative to those associated with K and Cl impurities. The relationship between the results presented here and some features in the infrared reflection spectra of non-dilute alloys is discussed.     

Lattice energy of alkali halide crystals

A new repulsive term in the ionic interaction potential ψ(r) = Ar^?ne^?r/gl, is suggested and the three unknown parameters A, λ and n are evaluated. Lattice energies of alkali halide crystals are calculated using this form. The results agree fairly well with the experimental values.     

Optical absorption in complex TCNQ salts

Optical absorption spectra of complex TCNQ salts (Qn, 2-2' BIP, 4-4' BIP, NMePy and MEM) compressed into KBr were measured. It is demonstrated that the low energy transition around 0.3 eV appears in all cases, but is not simply related to the transport properties. Powder optical spectra can not be used to determine the strength of Coulomb interaction in these materials.     

New potential energy function for alkali halide molecules

A new repulsive term in the ionic interaction potential for computing the lattice energy, the rotational constant (α₀) and the vibrational constant (w₀x₀) of alkali halide molecules has been proposed as $\text{ψ(r) = Af}{}^{\mathrm{n}}\text{r}{}^{\mathrm{-n}}\text{e}{}^{\mathrm{<mtext>?r</mtext><mtext>\lambda </mtext>}}$, which apart from being generalised, dimensionally homogenous and physically sound yields better values for lattice energy, α₀ and w₀x₀ than the previously reported potentials models.     

Phase transition of quaternary alkyl halide salts of diazabicyclo [2.2.2] octane

A series of quaternary alkyl halide salts of diazabicyclo [2.2.2] octane were found to exhibit first-order phase transitions at 64–103°C. Drastic changes of halide anion conductivities by three to four orders of magnitude were found to occur at the transition temperatures. X-ray diffractions of powdered sample revealed that the transition was induced by a structural change of the crystal. Differential scanning calorimetries were also measured.     

Threshold of F-center formation of alkali halide crystals by two-photon absorption

Thresholds of F-center formations for various alkali halide crystals with accuracy better than 5 meV are first reported by two-photon absorption process of a tunable dye laser.     

The influence of compression on the absorption of AgBr single crystals

The influence of compression on the edge of self absorption of AgBr single crystals was studied. The measurements were performed at a temperature of –180°C. The shift of the edge of self absorption was studied both in the field of elastic and plastic deformations. The shift of the absorption edge towards the UV end of the spectrum was determined in the field of elastic deformations and towards the i.r. end in the field of plastic deformations. After the ending of the deformation and after unloading the crystal the return of the absorption edge towards the original position was observed.

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AgBr

AgBr. –180°C. , . , — . .

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The author thanks Prof. Dr. L. Zachoval and K. K. Vacek C. Sc. for their interest in this work and for many comments given during the work.     

On the angular momentum transferred during electromagnetic energy absorption and emission

In the framework of classical electrodynamics, the angular momentum transported into (and/or from) a volume bounded by a rotational surface is derived. The dependences of electromagnetic field on space and time, and also the electromagnetic properties of the interacting masses are arbitrary. The results may be useful for the theory of toroidal currents induced by high-frequency heating of plasmas. A connection with the Manley-Rowe equations is given.     

Volume absorption laser energy meter for high energy laser by water absorption

Since the energy density of high energy laser can be extremely high and destructive, it is difficult to directly measure the laser energy with custom methods. A volume absorption method directly using water as absorption substance is introduced. In the energy meter, water is pumped into an absorption cavity sealed by a quartz window, and energy increment of water by laser is calculated. The new energy meter has excellent power and energy linearity and is almost not affected by power, energy and flow, its relative deviation to norm middle-power energy meter is 1.9 %, which infers that the new energy meter can measure higher laser energy and maintain higher precision as well.     

Photoelectric work function changes during heterogeneous adsorption of alkali halide molecules on alkali halide crystals

The changes of photoelectric work function during heterogeneous adsorption of alkali halide crystals had been observed. They were attributed to the non-zero effective dipole moment of the adsorbed layer, and were estimated using the Helmholtz formula. Measurements of this effect showed semi-quantitative agreement with the theoretical model. The divergences between experimental data and theoretical calculations were briefly discussed.     

A simple formula for the fundamental optical absorption of alkali halide melts

Significant similarities — with respect to absorption of ultraviolet — between the crystalline and liquid phases of the alkali halides are considered. It is shown that a simple formula which emerged from an earlier application of local electron transfer concepts to the fundamental absorption of the alkali halide crystals appears to apply equally well (i.e. within experimental error) to their melts. This formula fits the observations relating to the fundamental absorption of five molten alkali halides and yields predictions for all the others — which will, it is hoped, stimulate experimental activity.     

Effect of a magnetic pulse compression circuit on the operation of a halide laser

A magnetic pulse compression (MPC) circuit is used to investigate the operation of a thyratron and the output parameters of a copper chloride laser as a kind of halide copper vapor laser. The inverse voltage on the thyratron anode, maximum and rise time rate of the current, and losses of the thyratron are determined and compared in circuits with MPC and without MPC. Experimental data shows that, in the circuit with MPC, the lifetime of the thyratron is increased, and the output power of the laser is also increased by about 60%, while the width of the optical output is decreased by up to 53%.     

Optical absorption in crystals and solutions of potassium halides with lead halide impurity

Using a spectrophotometric method of determining lead concentrations, the relation between the optical absorption of alkali-halide crystals with PbCl₂ impurity and that of the corresponding aqueous solutions was investigated. It was shown that the differences in the position of absorption maxima of (MHal_n)^m- complexes are determined by the effect of water molecules, and not by the structure of the complexes. It is established that the long-wave absorption band in the crystal (273 nm in KCl + PbCl₂) is due to the interaction of lead ions with anions, independently of the nature of the distribution of the impurity in the crystal.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 71–76, December, 1971.