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

Abstract

Spectral, temperature, and baric dependences of birefringence Δn_i of LiNaSO₄ (LSS) crystals have been studied. It is established that dispersion Δn(λ) is anomalous. It is shown that uniaxial compression leads to changes in Δn_і with different magnitudes and signs. The dispersion effect of changes in Δn_і decreases under stress \(\sigma \, \bot \, z\) and increases in the opposite case (σ || z). Pressure-induced changes in the refractive index are estimated; it is established that the refractive indices of an LSS crystal increase under uniaxial compression, which may be related to compression of the crystal and change in its interatomic bond nature.