CAREER: Development of Single Molecule Infrared and Visible Absorption Spectroscopies using Optical Trapping Force Detection

在化学系化学测量和成像项目的支持下，耶鲁大学的加尼姆教授正在研制一种显微镜，它将灵敏度（低至一个分子）与广泛的兼容性（任何分子、任何溶剂环境、生物/非生物反应性等）结合起来，并产生任何化学家都能解释的直接光谱数据。加尼姆教授将超快红外光谱与精密力显微镜相结合，帮助科学家观察化学反应中发生的中间体的分布。研究结果可以为全面量化自然发生的分子结构分布提供新的实验和理论见解。加尼姆教授还参与了校园内的三个教育项目。示范项目包括让学生使用研究级光学陷阱在微观世界中拉动和推动的互动演示，以及建造并带回家功能光谱仪和显微镜的讲习班。当测量复杂混合物中的反应动力学变得足够简单，化学家可以将其应用于研究失败反应的机制时，变革性的进展将有可能推动该支持项目。Ganim教授以溶液中力检测纳米级吸收光谱的最新发展为基础，开发了适合化学动力学实验的单分子（SM）红外光谱。具体来说，Ganim教授和他的团队开发了一个预测模型来解释光诱导信号的大小，并指导定制纳米结构力探针的合成。传统的SM荧光用于独立验证单分子灵敏度。然后将这些增强功能与多路复用、时域实现和最大似然信号处理结合使用，以实现SM红外光谱。该技术随后被用于观察单铱（III）氢化物配合物中的实时配体交换，该配合物以其催化加氢和脱氢特性而闻名。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Ganim at Yale University is building microscopes that combine sensitivity (down to one molecule) with broad compatibility (any molecule, any solvent environment, bio/non-biological reactivity, etc.) and produce straightforward spectral data that any chemist can interpret. Professor Ganim uses a combination of ultrafast infrared spectroscopy with precision force microscopy to help scientists to watch the distribution of intermediates occurring in a chemical reaction one at a time. The results could provide new experimental and theoretical insights to comprehensively quantify distributions of molecular structures that naturally occur. Professor Ganim also works with three educational initiatives on campus. Exemplary projects include interactive demonstrations for students to pull and push at the microscopic world using a research-grade optical trap and workshops to build and take home a functional spectrometer and microscope.The support project is motivated by the transformative progress that will be possible when measuring reaction kinetics in complex mixtures is simple enough that chemists will apply it to study the mechanisms of failed reactions. Professor Ganim builds on the recent development of force-detected nanoscale absorption spectroscopy in solution and develops single molecule (SM) infrared spectroscopy suitable for chemical kinetics experiments. Specifically Professor Ganim and his group develop a predictive model to explain the photoinduced signal magnitude and to guide the synthesis of custom nanostructured force probes. Traditional SM fluorescence is used to independently verify single molecule sensitivity. These enhancements are then used in conjunction with a multiplexed, time-domain implementation and maximum-likelihood signal processing to realize SM infrared spectroscopy. The technique is then used to observe real-time ligand exchange in single iridium(III) hydride complexes, which are known for their catalytic hydrogenation and dehydrogenation properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.