Dynamics of Molecules in Crystals: X-ray Crystallographic Analysis and Development of Functional Materials

Abstract

This review presents some of our studies on dynamic processes of molecules in crystals, which are related to orientational changes of organic molecules and photochromic reactions in crystals. The dynamic processes of molecules were studied by analyzing disorders in the crystal structures and their changes induced by temperature changes or photoreactions. Development of functional crystalline materials is also reviewed, especially focusing on plastic/ferroelectric molecular crystals that showed unique ferroelectric properties, which are due to the cubic crystal structures resulting from an isotropic molecular rotation in the plastic crystal phases.