Thermal Motion in Sodium Nitrite: The Temperature Dependence of Debye-Waller Factors

Abstract

In order to understand the relation between the transition mechanism and the thermal vibration, the temperature dependence of the Debye-Waller factor is investigated in NaNO 2 by single-crystal X-ray diffractometry. The crystal parameters are refined by least squares calculations both in paraelectric and ferroelectric phases. The maximum entropy method is also employed to estimate the spontaneous polarization. The Debye-Waller factor displays a minor anomaly at the order-disorder transition point. The result is compared with K 2 SeO 4 , a typical displacive crystal.