| 摘要: | 摘要： A tilted two-layer colloidal system is constructed for the study of force-assisted barrier-crossing dynamics over a periodic potential. The periodic potential is provided by the bottom layer colloidal spheres forming a fixed crystalline pattern on a glass substrate. The corrugated surface of the bottom colloidal crystal provides a gravitational potential field for the top layer diffusing particles. By tilting the sample at an angle with respect to the vertical (gravity) direction, a tangential component of the gravitational force F is applied to the diffusing particles. The measured mean drift velocity v( F , E b ) and diffusion coefficient D ( F , E b ) of the particles as a function of F and energy barrier height E b agree well with the exact results of the one-dimensional drift velocity (R. L. Stratonovich, Radiotekh. Elektron , 1958, 3 , 497) and diffusion coefficient (P. Reimann, et al. , Phys. Rev. Lett. , 2001, 87 , 010602 and P. Reimann, et al. , Phys. Rev. E , 2002, 65 , 031104). Based on these exact results, we show analytically and verify experimentally that there exists a scaling region, in which v( F , E b ) and D ( F , E b ) both scale as ν ′( F )exp[− E * b ( F )/ k B T ], where the Arrhenius pre-factor ν ′( F ) and effective barrier height E * b ( F ) are both modified by F . The experiment demonstrates the applications of this model system in evaluating different scaling forms of ν ′( F ) and E * b ( F ) and their accuracy, in order to extract useful information about the external potential, such as the intrinsic barrier height E b . A tilted two-layer colloidal system is constructed for the study of force-assisted barrier-crossing dynamics over a periodic potential. The periodic potential is provided by the bottom layer colloidal spheres forming a fixed crystalline pattern on a glass substrate.
其他題名： Soft Matter
出版者： England
出版日期： 2015-02-14
出處： Soft matter, 2015-02, Vol.11 (6), p.1182-1196
識別號： ISSN: 1744-683X
識別號： ISSN: 1744-6848
識別號： EISSN: 1744-6848
識別號： DOI: 10.1039/c4sm02387k
識別號： PMID: 25562695 |
