CORRELATED ORIENTATIONS IN NANOCRYSTAL FLUCTUATIONS

The dynamical behavior of small particles has been observed by high re solution electron microscopy. Spontaneous structural fluctuations, bet ween various orientations, were observed and quantified. Clear transit ions involving appearance and vanishing of twins were detected. Measur ements of the angle change between succeeding configurations of the [1 11] atomic plane reveal the existence of several preferred angular cha nges. Twin related transformations give a good fit to the observed ang ular correlation, which excludes complete particle melting during the transition between successive configurations. It was also found that t he particles rotate by a few degrees during this transformation.