We report on time dependent Stokes shift measurements of single molecules. Broadband excitation and emission spectroscopy were applied to study the temporal Stokes shift evolution of single perylene diimide molecules (PDI) embedded in a polymer matrix on the time scale of seconds. The Stokes shift varied between individual molecules as well as for single molecules undergoing different conformations and geometries. From the distribution and temporal evolution of Stokes shifts, we unravel the interplay of nano-environment and molecular conformation. We found that Stokes shift fluctuations are related to simultaneous and unidirectional shifts of both emission and excitation spectra.
Probing the Conformations of Single Molecule via Photon Counting Statistics
提出了一种利用光子计数统计检测单分子构象的方法。用推广的Smoluchoswki方程描述单分子构象变化的动力学过程。在构象坐标$\bm{\mathcal{X}}$和外场频率$ω_L$空间($\bm{\mathcal{X}}-ω_L$空间)中,发射光子数$<N >$和Mandel的$Q$参数的共振轨迹可以用来重建单分子的构象.作为一个例子,我们考虑硫磺素T分子。结果表明,用光子计数统计方法提取的构象与{ \it ab initio}计算的结果吻合得很好。
Conformational heterogeneity of molecules physisorbed on a gold surface at room temperature
由于暴露于空气中的分子的快速结构动力学,在室温下的定量单分子尖端增强拉曼光谱(TERS)研究仍然是一个挑战。在这里,我们展示了高光谱TERS成像的单个或几个灿烂的甲酚蓝(BCB)分子在室温下,随着定量光谱分析。通过使用薄Al $_{2}$ O $_{3}$覆盖层的定格方法实现了稳健的化学成像,该覆盖层抑制光谱扩散并抑制空气中的化学反应和污染。对于在TERS图像中空间分辨的分子,观察到高达7.5 cm $^{-1}$的清晰拉曼峰变化,这在分子系综中找不到。从密度泛函理论为基础的定量分析不同的TERS峰,我们揭示了在单分子水平上的构象异质性。这一工作为研究相互作用介质中的单分子性质提供了一种简便的方法,拓展了单分子振动光谱的研究范围。
Chemistry-Enhanced Diffusion-Based Framework for Small-to-Large Molecular Conformation Generation
SCNU Environmental Research Institute(华南师范大学环境研究院);Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety(广东省化学污染与环境安全重点实验室);School of Environment, South China Normal University(华南师范大学环境学院);MOE Key Laboratory of Environmental Theoretical Chemistry(教育部环境理论化学重点实验室)
Cooperative Conformational Transitions in Macromolecules under Mechanical Stretching. An Exactly Solved Model for Single Molecule Experiments
University of Barcelona(巴塞罗那大学);University of Lleida(莱里达大学);Institute for Bioengineering of Catalunya (IBEC)(加泰罗尼亚生物工程学院);The Barcelona Institute of Science and Technology (BIST)(巴塞罗那科学与技术研究院)
Learning Neural Generative Dynamics for Molecular Conformation Generation
Mila - Québec AI Institute(米拉-魁北克人工智能研究所);Université de Montréal(蒙特利尔大学);Peking University(北京大学);Canadian Institute for Advanced Research (CIFAR)(加拿大高等研究院);University of Illinois at Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);HEC Montréal(蒙特利尔高等商学院)