Dynamical fluctuations in proteins, organic semiconductors, and nanoparticle catalysts

康奈尔大学的罗杰·洛林得到了化学系化学理论、模型和计算方法计划颁发的奖项的支持，以开发详细的模型和执行计算，以解释和激发分子运动的新测量。分子的运动决定了化学和生物过程，以及材料的机械和电子性能。最近的实验技术在更小的长度尺度和更短的时间尺度上获得了关于这些运动的信息。洛林和他的研究生同事模拟了蛋白质等生物分子中的机械振动和能量流动，小金粒子表面催化的化学反应中的个别事件，以及有可能用于塑料电子产品的分子半导体中的电荷载流子传输。研究生通过康奈尔大学协调的教师培训和丰富项目为K-12教育做出贡献。多维振动光谱探测生物分子的结构和松弛，但完整的解释需要用原子水平的细节来模拟测量。基于半经典平均轨道方法的计算非线性振动响应函数的新方法使用经典模拟的输入近似量子动力学。电场显微镜具有测量无序有机半导体中载流子动力学的能力。从经典统计力学和经典电动力学出发，对电动力显微镜、非接触摩擦和探头频率噪声等能观量进行了计算，揭示了这些量与有机电子器件中电荷输运之间的联系。纳米颗粒催化的单周转研究测量了在整体测量中观察到的平均动力学的波动。洛林和他的同事开发了金属纳米结构上不同活性部位化学事件之间在时间和空间上的相关性的统计方法，阐明了无机催化剂中酶的变构效应的类似物。

Roger Loring of Cornell University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry division to develop detailed models and perform calculations that interpret and motivate new measurements of molecular motions. The motions of molecules determine chemical and biological processes, as well as mechanical and electronic properties of materials. Recent experimental techniques obtain information regarding these motions on ever smaller length scales and shorter time scales. Loring and graduate student coworkers model mechanical vibrations and energy flow in biomolecules such as proteins, individual events in chemical reactions catalyzed by the surface of small gold particles, and charge carrier transport in molecular semiconductors with the potential for use in plastic electronics. Graduate students contribute to K-12 education through teacher training and enrichment programs coordinated by Cornell University.Multidimensional vibrational spectroscopy probes structure and relaxation in biomolecules, but full interpretation requires modeling the measurement with an atomic level of detail. New methods for computing nonlinear vibrational response functions based on the semiclassical mean-trajectory approach approximate quantum dynamics using input from classical simulations. Electric force microscopy has the capacity to measure charge carrier dynamics in a disordered organic semiconductor. Calculations from classical statistical mechanics and classical electrodynamics of the observables of electric force microscopy, noncontact friction and probe frequency noise, reveal the connections between these quantities and charge transport in an organic electronic device. Single-turnover studies of nanoparticle catalysis measure fluctuations from the mean kinetics observed in a bulk measurement. Loring and coworkers develop statistical measures of correlations in time and space among chemical events at different active sites on metal nanostructures, elucidating the analogs in inorganic catalysts of allosteric effects in enzymes.