Baric Shift of Phase Transition in Ammonium Sulfate Crystals

The influence of uniaxial mechanical pressures ($σ_m$ ≤ 200 bar) on the spectral (300-800 nm) and temperature (77-300 K) dependences of the refractive indices $n_{i}$, the birefringence $Δn_{i}$ and the phase transition point in ammonium sulfate crystals are studied. It is established that the uniaxial pressure does not change character of the dispersion $dn_{i}$/dλ, but only its value λ The shift of the phase transition in ammonium sulfate under the uniaxial mechanical pressure is analyzed.