Using real-space imaging of single particles, we investigate the interplay between translational and rotational motion of tracer particles in suspensions of colloidal particles over a wide range of volume fractions from dilute fluid to densely packed crystal. To this end, we introduce a new type of spherical colloidal tracer particles containing two differently labelled fluorescent cores. The tracer particles can be combined with host particles enclosing a single fluorescent core and chemical and physical properties identical to the tracers. This leads to a system of spherical colloidal particles, in which spatio-temporal trajectories of rotation and translation of individual particles can be recorded simultaneously with full 360° resolution of rotational dynamics. Our analysis shows that translation and rotation of colloidal particles are uncorrelated and decoupled for all volume fractions irrespective of the phase of the particle system.

中文翻译：

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硬球从流体到晶体的平移和旋转动力学的真实空间成像

使用单个粒子的真实空间成像，我们研究了在从稀释液到稠密晶体的大体积分数范围内，示踪剂粒子在胶体粒子悬浮液中的平移和旋转运动之间的相互作用。为此，我们介绍了一种新型的球形胶体示踪剂颗粒，其中包含两个标记不同的荧光核。示踪剂颗粒可以与包围单个荧光核且化学和物理性质与示踪剂相同的主体颗粒结合。这导致了球形胶体粒子系统，其中单个粒子的旋转和平移的时空轨迹可以同时以完整的360°旋转动力学分辨率进行记录。