Optical activity of KH₂PO₄

Abstract

By applying the improved HAUP method, measurements of gyration tensor g ₁₁ of KH₂PO₄ (KDP) were made with application of biasing electric fields up to 20 kv/cm. It was found that the gyration tensor with zero electric field manifests a sharp peak at Tc and it becomes depressed depending on magnitude of the electric fields. Moreover, gyration tensor g ₁₁ of KD₂PO₄ (DKDP) was measured, and it was confirmed that the temperature dependence of the gyration tensor obeys the Curie-Weiss law as is the case with KDP. Then the Curie constants for KDP and DKDP were obtained as 6.90 × 10⁻⁴ K and 1.10 × 10⁻³ K respectively.