52 Result(s)
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A. F. Konstantinova
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Article
Structure and Optical Properties of Langasite Family Crystals (La1–xNdx)3Ga5SiO14 (x = 0, 0.4, 0.6, 1)
The structure and optical properties of langasite family crystals (La1–xNdx)3Ga5SiO14 with different Nd contents have been studied. The optical rotation ρ for these crystals has been calculated from the measured ...
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Article
Measurement and Calculation of the Refractive Indices of Langasite-Family Crystals Sr3NbFe3Si2O14, Ba3NbFe3Si2O14, and Ba3TaFe3Si2O14 and the Relationship of Optical Activity with Peculiarities of Electron-Density Distribution
The optical properties of Sr3NbFe3Si2O14, Ba3NbFe3Si2O14, and Ba3TaFe3Si2O14 single crystals (promising multiferroics belonging to the langasite family (sp. gr. P321, Z = 1)) have been investigated. The crystals ...
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Article
Peculiarities of Electric Properties of Various Materials
Examples of electric properties of various crystalline materials, insulators and semiconductors, liquid crystals, films, and nanostructures are presented. Among crystals, particular attention is paid to piezoe...
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Article
Some Optical and Mechanical Properties of Right- and Left-Handed Langasite Family Crystals and Their Structural Basis
Some optical and mechanical properties of a number of langasite family crystals have been compared. It is shown that electron-density regions in the form of helices, twisted in the opposite directions for the ...
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Article
Anisotropy of Microhardness and Fracture of Langasite Crystal and Its Structural Basis
The anisotropy of microhardness and fracture of the (0001) basal plane of langasite crystal has been studied using Berkovich indentation under a load of 100 g at different indenter positions. The formation of ...
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Article
Magneto-Optical Effects in Various Crystalline Materials, Films, and Meso- and Nanostructures
Examples of manifestation of magneto-optical Faraday, Cotton–Mouton, and Kerr effects in some crystals and artificial materials are considered. Most attention is paid to the Faraday effect: optical activity ma...
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Article
Features of Optical Activity in Inorganic and Organic Materials
The possibilities of manifestation of optical activity in different media (photonic crystals, metamaterials, and liquid crystals) are considered. Some interesting examples of optically active crystals are demo...
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Article
Central Peak in the Raman Spectra of Quartz Crystals in a Wide Temperature Range
The spectral intensity of Raman scattering in quartz crystals has been calculated in a wide temperature range including the point of the α–β phase transition. It is established that a central peak is present i...
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Article
Search for Helices of Atomic Electron Density As a Structural Basis of Optical Activity in α-TeO2 Crystal
An X-ray diffraction study of the atomic structure of paratellurite (α-TeO2) crystal in the temperature range of 86–500 K has been performed. Regions of atomic electron density, shaped as helices with axes orient...
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Article
Raman Scattering in Langasite-Family Crystals
Raman scattering spectra have been investigated in La3Ga5SiO14 langasite crystals with Cr and Fe impurities and La3Ga5.25Ta0.25Si0.5O14 crystalline solid solution. It is shown that all spectra contain a low-frequ...
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Article
Determination of the Optical Parameters of Uniaxial Optically Active Crystals Taking into Account the Imperfection of Spectrophotometric Complex Elements
The influence of the imperfection of optical elements of a spectrophotometric system on the polarization transmission spectra of a uniaxial optically active absorbing plate has been analyzed by the example of ...
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Article
Determination of the Optical Parameters of Uniaxial Crystals with Allowance for the Imperfection of the Spectrophotometric Complex Elements
The influence of the imperfection of a polarizer, an analyzer, and a photoelectron multiplier of a spectrophotometric complex on the intensity of light passed through a plane-parallel plate of a uniaxial trans...
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Article
Anisotropy of Optical Activity in Langasite Family Crystals
The rotation of the plane of polarization of light transmitted in the directions parallel (ρ||) and perpendicular (ρ⊥) to the optical axis has been calculated for langasite family crystals. It is shown that the ρ
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Article
Manifestation of optical activity at oblique incidence of light in crystals of classes \(\overline 4 \) 2m and \(\overline 4 \)
The polarization azimuths and ellipticities of the reflected and transmitted light have been calculated as functions of the angle of incidence for transparent crystals of classes
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Article
Influence of the antisymmetric part of gyration pseudotensor on the characteristics of transmitted light in biaxial crystals
The influence of the antisymmetric part of gyration pseudotensor on the characteristics of transmitted light have been investigated for biaxial crystals. Analytical expressions for the optical rotation in the ...
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Article
Specific features of optical activity in various uniaxial crystals
The influence of the antisymmetric part of the gyration pseudotensor on the characteristics of reflected and transmitted light has been considered for crystals of classes 3, 4, and 6. The results are compared ...
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Article
Experimental and theoretical determination of the optical rotation in langasite family crystals
Optical properties of 21 langasite family crystals of different compositions have been studied. Dispersion dependences of the specific optical rotation for light propagation along the optical axis are experime...
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Article
Chiral symmetry breaking in complex chemical systems during formation of life on earth
The chiral symmetry in complex chemical systems containing many amino acids and characterized by many similar chemical reactions (a situation corresponding to the formation of life on Earth) is considered. It ...
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Article
On the structural basis of the presence of two optical axes in α-HIO3 crystal
An X-ray diffraction study of α-HIO3 crystal has been performed with the following results: sp. gr. P212121, Z = 4, a = 5.5360(3) Å, b = 5.8723(6) Å, c = 7.7291(5) Å, and R factors R(F)/wR(F) = 0.86/0.69%. Disord...
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Article
Manifestation of optical activity in different materials
Various manifestations of optical activity (OA) in crystals and organic materials are considered. Examples of optically active enantiomorphic and nonenantiomorphic crystals of 18 symmetry classes are presented...
