Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.
Science. 2017 Feb 3;355(6324):494-498. doi: 10.1126/science.aah3582.
In real time and space, four-dimensional electron microscopy (4D EM) has enabled observation of transient structures and morphologies of inorganic and organic materials. We have extended 4D EM to include liquid cells without the time resolution being limited by the response of the detector. Our approach permits the imaging of the motion and morphological dynamics of a single, same particle on nanometer and ultrashort time scales. As a first application, we studied the rotational dynamics of gold nanoparticles in aqueous solution. A full transition from the conventional diffusive rotation to superdiffusive rotation and further to a ballistic rotation was observed with increasing asymmetry of the nanoparticle morphology. We explored the underlying physics both experimentally and theoretically according to the morphological asymmetry of the nanoparticles.
在实时和空间中，四维电子显微镜（4D EM）使人们能够观察无机和有机材料的瞬态结构和形态。我们已经将 4D EM 扩展到包括液体池，而不会受到探测器响应的时间分辨率的限制。我们的方法允许在纳米和超短时间尺度上对单个相同粒子的运动和形态动力学进行成像。作为第一个应用，我们研究了金纳米粒子在水溶液中的旋转动力学。随着纳米粒子形态不对称性的增加，观察到从常规扩散旋转到超扩散旋转，再到弹道旋转的完全转变。我们根据纳米粒子的形态不对称性进行了实验和理论上的探索。
