Barium fluoride crystals

To optimize the conversion efficiency, physical focusing conditions need to be optimized. With reference to the SG spectrum shown in Fig. 5.8, for fixed incident laser power and fixed focal length of the lens, the location of the focus point within the 7.5 cm long barium fluoride crystal was found to determine the extent of the white light spectrum. With the focus located f cm inside the crystal, the flattest possible spectrum of white light was obtained (as shown in Fig. 5.8), and the highest conversion efficiency was also achieved. 

The use of infrared spectrophotometry in clinical chemical problems on an ultramicro scale has been described by Stewart et oZ. (S13, S14). Two drops of serum or other body fluids are spread out between the barium fluoride crystal windows of the sample cell. A light path of... 

Barium fluoride [7782-32-8] Bap2, is a white crystal or powder. Under the microscope crystals may be clear and colorless. Reported melting points vary from 1290 (1) to 1355°C (2), including values of 1301 (3) and 1353°C (4). Differences may result from impurities, reaction with containers, or inaccurate temperature measurements. The heat of fusion is 28 kj/mol (6.8 kcal/mol) (5), the boiling point 2260°C (6), and the density 4.9 g/cm. The solubiUty in water is about 1.6 g/L at 25°C and 5.6 g/100 g (7) in anhydrous hydrogen fluoride. Several preparations for barium fluoride have been reported (8—10). 

Materials. Beside inorganic materials (eg, barium chloride/fluoride crystals, doped with 0.05% samarium), transparent thermoplasts are preferred for the PHB technique, eg, poly (methyl methacrylate) (PMAIA), polycarbonate, and polybutyral doped with small amounts of suitable organic dyes, organic pigments like phthalocyanines, 9-arninoacridine, 1,4-dihydroxyanthraquinone [81-64-1] (quinizarin) (1), and 2,3-dihydroporphyrin (chlorin) (2). 

Goldschmidt predicted from his empirical rule that calcium chloride would not have the fluorite structure, and he states that on investigation he has actually found it not to crystallize in the cubic system. Our theoretical deduction of the transition radius ratio allows us to predict that of the halides of magnesium, calcium, strontium and barium only calcium fluoride, strontium fluoride and chloride, and barium fluoride, chloride,... 

Direct visualization of femtosecond filamentation is crucial to understanding the phenomenon. As the energy of a single infrared photon is much too small to effect an electronic transition, one has to take recourse to multiphoton absorption induced fluorescence to come up with a scheme to directly visualize filamentation in condensed media. One such scheme that has been successfully implemented involves the use of a crystal of barium fluoride, a material that is known to be very good scintillator [38]. 

Figure 5.2 shows that the onset of collapse in barium fluoride as the incident power is varied from 110 PCT to 1,200 Pcr. The onset of filamentation, z0f, the filament start position (the arrow in each panel marks the onset position), varies from 4.6 mm inside the crystal at 110 PCI to a position that is located on the incident face of the crystal at 1,200 PCI. Note that the images in Fig. 5.2 indicate that multiple filamentation occurs within the crystal at such high power levels. 

For jumps involving single point defects, is accurately known for the different crystal structures. Ionic conductivity measurements, coupled with other diffusion measurements, have proved to represent a very powerful method for identifying diffusion mechanisms. However, the requirement for single-crystal samples proved to be very restrictive in terms of the materials that could be investigated, and the approach has been used successfully only for very simple systems. Examples include the combination of conductivity and diffusion in the study of alkali and silver halides [226], and the combination of conductivity and NMR in the study of barium fluoride [219]. 

Barium fluoride, Bap2 9.2 Crystal growth issues ... 

INTRODUCTION This data sheet provides information for synthetic single crystal barium fluoride. 

BaF, (barium fluoride) 0.149 13.51 67000 740 19417 214 1.46 Brittle crystal insoluble in water good resistance to fluorine and fluorides. 

Barium fluoride (Fp. 1355 °C solubility in water 1 g/1 at 20 °C) is used in aluminium metallurgy, in enamel and glazing frits and in the production of arc welding agents. Single crystal barium fluoride is employed in combination with gallium arsenide as insulator for semiconductor devices [62]. Bap2 can be synthesized by precipitation in a reaction of a water-soluble barium salt with aqueous HF. 

These incorporate membranes fabricated from insoluble crystalline materials. They can be in the form of a single crystal, a compressed disc of micro-crystalline material or an agglomerate of micro-crystals embedded in a silicone rubber or paraffin matrix which is moulded in the form of a thin disc. The materials used are highly insoluble salts such as lanthanum fluoride, barium sulphate, silver halides and metal sulphides. These types of membrane show a selective and Nemstian response to solutions containing either the cation or the anion of the salt used. Factors to be considered in the fabrication of a suitable membrane include solubility, mechanical strength, conductivity and resistance to abrasion or corrosion. 

Nowadays a large number of functional crystals belongs to the TTB family and presents electro-optic, ferro- piezo- pyroelectric properties (e g. the well-known barium sodium niobate Ba2NaNb50i5 (BNN)). In this work iron and manganese based Kx(lvr%(]Vr )i-xF3 fluorides (0.4solid state reaction and characterised by different diffraction techniques in order to investigate their crystalline stmcture. 

Because barium titanate has interesting properties, many methods have been used to grow single crystals of this compound. One of the most popular techniques, using a potassium fluoride flux, was first employed by Remeika.1... 

Crystals of barium titanate can be grown with a mixture of 30% barium titanate by weight and anhydrous potassium fluoride. In a... 

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