Structural instability of ultrafine particles of metals

Abstract

Dynamic behavior of ultrafine particles of gold around 20 A\r{} in size was examined at the level of the atomic resolution by an electron microscope equipped with a real-time video recording system. In real time, it was observed that the shape of the particles changed continually through an internal transformation from a single crystal to a twinned crystal, and vice versa. The transformations were induced to some extent by the irradiation of the electron beam. They took place abruptly in less than 0.1 sec.