Potassium Chloride Single Crystals Research Articles

Growth and characterization of semi-organic, third-order nonlinear optical (NLO) phthalic acid potassium chloride (PAPC) single crystals

Growth and characterization of semi-organic, third-order nonlinear optical (NLO) phthalic acid potassium chloride (PAPC) single crystals

Investigation on optical, thermal, dielectric and mechanical properties of antimony potassium tartrate on l-alanine single crystals

Antimony potassium tartrate l-alanine potassium chloride single crystals have been grown by slow evaporation solution growth technique. The cell parameters were estimated from single crystal X-ray diffraction analysis and it was found that the material crystallizes in orthorhombic symmetry. The powder X-ray analysis proved its crystalline nature without the formation of secondary phases. The presence of functional groups and the nature of bonds appearing in the material were identified by FTIR spectroscopy. Optical constants were estimated by UV–Vis spectrum and the lower cut off wavelength was observed at 265 nm. Photoluminescence emission spectrum show violet band through a strong peak centered at 419.96 nm. The scanning electron microscope analysis has been carried out to determine the surface morphology of the grown crystal. Energy dispersive spectrum was done to identify the composition of elements present in the title material. The second harmonic generation efficiency of the sample was confirmed and measured by Kurtz powder technique which reveals that the conversion efficiency was found to be 0.437 times that of KDP. The thermal, dielectric and mechanical studies were carried out for the title material. The obtained results show that antimony potassium tartrate l-alanine crystals are potential materials in NLO device applications.

Nucleation kinetics and dielectric characterization of L-Proline Potassium Chloride (LPPC) single crystals

Nucleation kinetics and dielectric characterization of L-Proline Potassium Chloride (LPPC) single crystals

Synthesis, growth and characterization of l-Alanine Potassium Chloride single crystal: a phase-matchable semi-organic material for second and third order NLO applications

l-Alanine Potassium Chloride single crystals have been grown by slow evaporation solution growth technique. The cell parameters were estimated from single crystal X-ray diffraction analysis and it was found that the material crystallizes in orthorhombic symmetry with space group of P212121. The powder X-ray analysis proved its crystalline nature without the formation of secondary phases. The presence of functional groups and the nature of bonds appearing in the material were identified by FTIR spectroscopy. Optical constants were estimated by UV–visible spectrum and the lower cut off wavelength was observed at 330 nm. Photoluminescence emission spectrum show violet band through a strong peak centred at 380 nm. The scanning electron microscope analysis has been carried out to determine the surface morphology of the grown crystal. Energy dispersive spectrum was done to identify the composition of elements present in the title material. The second harmonic generation efficiency of the sample was confirmed and measured by Kurtz powder technique which reveals that the conversion efficiency was found to be two times that of urea crystal. Third order nonlinear optical susceptibility was identified using Z-scan technique and it is found that the crystal has a positive refractive index which is self focusing in nature. The obtained results show that l-Alanine KCl crystals are potential materials in NLO device applications.

Thermoluminescence and photoluminescence studies on γ-ray-irradiated Ce³⁺,Tb³⁺-doped potassium chloride single crystals.

Single crystals of KCl doped with Ce(3+),Tb(3+) were grown using the Bridgeman-Stockbarger technique. Thermoluminescence (TL), optical absorption, photoluminescence (PL), photo-stimulated luminescence (PSL), and thermal-stimulated luminescence (TSL) properties were studied after γ-ray irradiation at room temperature. The glow curve of the γ-ray-irradiated crystal exhibits three peaks at 420, 470 and 525 K. F-Light bleaching (560 nm) leads to a drastic change in the TL glow curve. The optical absorption measurements indicate that F- and V-centres are formed in the crystal during γ-ray irradiation. It was attempted to incorporate a broad band of cerium activator into the narrow band of terbium in the KCl host without a reduction in the emission intensity. Cerium co-doped KCl:Tb crystals showed broad band emission due to the d-f transition of cerium and a reduction in the intensity of the emission peak due to (5)D3 -(7)F(j) (j = 3, 4) transition of terbium, when excited at 330 nm. These results support that energy transfer occurs from cerium to terbium in the KCl host. Co-doping Ce(3+) ions greatly intensified the excitation peak at 339 nm for the emission at 400 nm of Tb(3+). The emission due to Tb(3+) ions was confirmed by PSL and TSL spectra.

Electrolytic coloration and spectral properties of hydroxyl-doped potassium chloride single crystals

Hydroxyl-doped potassium chloride single crystals are colored electrolytically at various temperatures and voltages using a pointed cathode and a flat anode. Characteristic OH − spectral band is observed in the absorption spectrum of uncolored single crystal. Characteristic O −, OH −, U, V 2, V 3, O 2−–V a +, F, R 2 and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current–time curve for electrolytic coloration of hydroxyl-doped potassium chloride single crystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained.

Color center formation in KCl and KBr single crystals with femtosecond laser pulses

Because of their extremely high instantaneous powers, femtosecond lasers can color many nominally transparent materials. Although the excitations responsible for this defect formation occur on subpicosecond time scales, subsequent interactions between the resulting electronic and lattice defects complicate the evolution of color center formation and decay. These interactions must be understood in order to account for the long-term behavior of coloration. In this work, we probe the evolution of color centers generated by femtosecond laser radiation in potassium chloride and potassium bromide single crystals on time scales from microseconds to hundreds of seconds. By using an appropriately chosen probe laser focused through the femtosecond laser spot, we follow the changes in coloration due to individual or multiple femtosecond pulses and the evolution of that coloration for long times after femtosecond laser radiation is terminated.

Investigation of the local mechanical properties of potassium chloride single crystals by atomic force microscopy

Using an atomic force microscope (AFM), the of hardness H and Young’s modulus E are measured in near-surface layers of KCl single crystals to a depth of 300 nm at loads of 5–100 µN. The values of H and E are estimated indirectly by analyzing P(h) curves (load vs. indentation depth curves). The value of H is also estimated directly by measuring the area of an indentation with the help of an AFM with a nanoscale resolution. The effect of structural features of the surface around an indentation on the accuracy of the H and E estimates is revealed. The sharp dependence of H on the load (the nanoscale effect) is revealed. The experimental results agree qualitatively with the predictions of the geometrically necessary dislocation model developed by Nix and Gao. However, in order to quantitatively estimate mass transfer from a nanoindenter, a structural analysis is required with allowance for plastic deformation in crystals.

DIFFUSION OF Tl+ IONS THROUGH THE INTERFACE OF SOLID NaCl, KCl OR RbCl AND LIQUID TlCl

The diffusion phenomena of thallous ions ( Tl + ions) through solid-liquid interface of liquid Tl + ions diffusion source and sodium chloride (NaCl) , potassium chloride (KCl) or rubidium chloride (RbCl) single crystals are studied by optical method. The characterisic absorption peaks of Tl + center in NaCl, KCl or RbCl single crystals were used as the tracer for measurements and the diffusion constants are evaluated at various temperatures. The results show that the diffusion constant of solid-liquid interface is about 103 times larger than that of solid-solid interface of KCl and TlCl .

Laser-stimulable transparent KCl:Eu crystals for erasable and rewritable optical memory utilizing photostimulated luminescence

Intense photostimulated luminescence (PSL) with a peak at 420 nm is observed in ultraviolet (UV)-light-irradiated europium-doped potassium chloride (KCl:Eu) single crystals. The PSL characteristics of UV-irradiated KCl:Eu for optical memory application are studied. The excitation and emission mechanisms of the 420 nm PSL, which are consistent with the results obtained, are discussed.

Dislocation charge in potassium chloride temperature and divalent-impurity dependence

Abstract Using the ultrasonic composite oscillator technique at high strain amplitudes (8 × 10−6-2 × 10−4) we have measured the equilibrium dislocation charge in bent potassium chloride single crystals doped with Ca2+ (0·02–14 p.p.m.) over the temperature range 400–730°C. The large strain amplitude ensures that dislocation displacement exceeds the Debye-Hückel screening radius so that the resulting polarization is unscreened. In the amplitude-dependent region the isoelectric temperature at which the mean charge vanished was found to decrease slowly with strain amplitude. The temperature and impurity dependences of the charge are well characterized by a straightforward model of vacancy formation at core jogs.

Growth of single crystals of potassium chloride from gels

AbstractThe growth of single crystals of potassium chloride (KCl) in silica gels upto 3 × 3 × 3 mm3 in size is described. To crystallize KCl incorporated in the gel, hydrochloric acid has been used to crystallize the KCl in the gel media. The crystalline perfection has been studied by the chemical etch pit technique.

Study of seed-melt interface in Czochralski grown potassium chloride single crystals by X-ray topography

Study of seed-melt interface in Czochralski grown potassium chloride single crystals by X-ray topography

The temperature dependence of dislocation charge in calcium doped single crystals of potassium chloride

Abstract Using the ultrasonic piezoelectric composite oscillator technique we have measured the temperature dependence of dislocation charge in bent KCl single crystals as a function of Ca impurity concentration. In each case the charge changes sign at an extrinsic isoelectric temperature, Te , and the shift in Te with impurity concentration allows the calculation of the individual thermodynamic vacancy formation parameters. We obtain h+ = 1.244±0.014 eV, s+ = 4.50±0.19 k, h- = 1.346∓ 0.014 eV and s- = 5.11∓0.19K.

Evidence for dislocation damping coefficient increases during gamma ray irradiation of sodium chloride and potassium chloride single crystals

Room-temperature radiation experiments have been carried out on deformed single crystals of ’’ultrapure’’ and nominally pure NaCl and KCl where it has been observed that the decrement may initially increase to some maximum value and then decreases with radiation time. In contrast, the compliance defect was always found to decrease as soon as the crystal was irradiated. If the radiation was stopped during an experiment the decrement kept on decreasing whereas the compliance defect remained essentially constant. Simpson and Sosin have observed a similar decrement maximum with copper foils vibrated at 500 Hz and exposed to 1.0-MeV electrons. Their defect-dragging model is examined in relation to the present work and it is concluded that the model cannot explain the results. The results are also compared with those of Anderson and Pollard who have carried out fast neutron irradiation experiments on NaCl and KCl crystals. It was found that the behavior of B/B0, the fractional change in the damping coefficient, is similar for both neutron and gamma ray experiments at least in the early stage of irradiation.

Bleaching of F-type centres in alkali halides. Part 1.—Photobleaching in KCl at room temperature

The photobleaching at ambient temperature of F and F2 centres in potassium chloride single crystals has been investigated using the pulse radiolysis method. Both F and F2 centres absorb in the F band region(ca. 560 nm at room temperature) and the rate of photobleaching of this band at constant incident light intensity is consistent with two different photolytic processes taking place. In the M band region (ca. 830 nm at room temperature) only the F2 centre absorbs and here the optical density initially increases and then decreases on photobleaching. Careful analysis of the data in both the F and M regions shows that under the prevailing experimental conditions photobleaching of both the F and F2 centres follows pseudo-first-order kinetics with rate constants consistent with the following scheme: F[graphic omitted]F2[graphic omitted] higher aggregate centres? The data have been used to obtain the relative oscillator strengths of the F(F), F2(F) and F2(M) bands and the values are compared with other estimates in the literature.

Spectroscopic and optically detected magnetic resonance studies of PO 2−in potassium chloride. I. Electronic and vibrational states

The phosphorescence and phosphorescence excitation spectra of phosphorus activated single crystals of potassium chloride have been examined at 4.2 K. The “color center” responsible for the blue emission in these samples is identified as PO 2 − by isotopic substitution and optically detected magnetic resonance measurements. The observed vibrational frequencies of the PO 2 − ion have been used to compute the normal coordinates of the ground state totally symmetric modes as well as the valuence angle in the valence force approximation. The vibrational analysis of the phosphorescence spectrum has been used together with the computed ground state normal coordinate description to compute the geometrical changes associated with excitation to the lowest triplet state of PO 2 −. The results for PO 2 − are compared with the results of similar calculations and measurements for other 18-electron AB 2 type molecules of the isoelectronic sequence PO 2 −, SO 2, NO 2 − and O 3.

Thermotransport of 85Sr and 54Mn in potassium chloride single crystals

The thermotransport of 85Sr and 54Mn tracers in single crystals of KCl was measured in the temperature range 950–1025 K, by means of Soret effect measurements. The mean value of the impurity heat of transport was −3.18±0.09 eV for Sr in pure or Sr-doped crystals, and was −5.45±0.83 eV for Mn in pure or Mn-doped crystals. There was no significant difference between values from pure and doped crystals for Sr, but for Mn this may not be the case. A discussion of the experimental and theoretical limitations of such measurements as a source of information about the heats of transport for individual jumps was given, and a comparison made with earlier thermotransport measurements in simple ionic solids.

Studies of the size and the misorientation of the mosaic blocks in pure and doped single crystals of potassium chloride

Extinction coefficients for pure and doped single crystals of potassium chloride have been measured with the use of polarized X-rays and subsequent analysis in terms of Zachariasen's theory of X-ray diffraction from real crystals. The sizes of the mosaic domains and the angles of misorientation between them have been determined from the extinction coefficients corresponding to copper and cobalt radiations. It has been observed that with increase in doping the sizes of the domains diminish and the misorientation between them increases.

Optical absorption and thermoluminescence of high a.c. field treated and X-ray irradiated potassium chloride single crystals

Optical absorption and thermoluminescence (TL) output measurements were made on high a.c. field treated and X-ray irradiated KCl single crystals. A substantial enhancement both in F-band peak absorption as well as in TL output was observed.