Temperature Dependence of the Refractive Indices of Doped K2SO4 Crystals

Journal of Applied Spectroscopy - The temperature dependence of the refractive indices of K2SO4 with copper impurity was investigated. It was found that introduction of the copper impurity leads to...     

Photoelastic Properties of Potassium Sulfate Crystals

Physics of the Solid State - The spectral dependences of the absolute piezooptic coefficients of potassium sulfate crystals are studied. It is established that their dispersion dependence is...     

On isotropic states in α-LiNH4SO4 crystals

The spectral and baric dependences of the birefringence of α-LiNH₄SO₄ crystals are studied. It is found that the birefringence is rather sensitive to uniaxial compressions. A baric shift of the isotropic point to longer or shorter wavelengths depending on the uniaxial compression direction is observed and a generalized temperature-spectral-baric diagram of the isotropic state is plotted. A possibility of the appearance of a pseudoisotropic state under the action of uniaxial pressure σ _z or simultaneous pressures σ _x = σ _z is shown.     

Pressure-Induced Changes in Parameters of the Indicatrix of Lithium Sodium Sulfate Crystals

Optics and Spectroscopy - Spectral, temperature, and baric dependences of birefringence Δni of LiNaSO4 (LSS) crystals have been studied. It is established that dispersion Δn(λ) is...     

On Isotropic Points in Potassium Ammonium Sulphate Crystals

Crystallography Reports - An effect of uniaxial pressure on the spectral and temperature dependences of birefringence of K1.75[NH4]0.25SO4 single crystals has been studied. Different changes in the...     

Energy Band Structure and Optical Properties of LiNaSO<Subscript>4</Subscript> Crystals

The energy band structure of a LiNaSO₄ has been calculated within the framework of density functional theory for space group P31c. It has been established that bandgap width E_g in the GGA approximation is 5.49 eV. The valence band top is generally formed of oxygen p-electrons, while the conduction band bottom is composed of lithium and sodium s-states. The effect of the cationic substitution Na → K → Rb → NH₄ on the electron structure of LiBSO₄ group crystals is considered. Based on the calculated dielectric functions, the spectral dependences of the refractive indices and extinction coefficient of a crystal were calculated and compared with experimental data.