Determination of the Gyration Tensor Components of Ammonium Rochelle Salt

The absolute optical chirality of sodium ammonium (+)-tartrate tetrahydrate crystals has been determined. The wavelength dispersion of the linear birefringence and the optical gyration tensor components were found at room temperature with the use of a high-accuracy universal polarimeter. The wavelength dispersion of the gyration is presented over the range 350-650 nm. The gyration coefficients at a wavelength of 500 nm were found to be g₁₁ = 12.5 × 10^-6, g22 = -36.0 × 10^-6 and g₃₃ = 6.7 × 10^-6. The results of the present work are in good agreement with values inferred by Koralewski & Szafranski [Ferroelectrics (1988), 80, 269-272].