New methods for linear and nonlinear Spectroscopy in inhomogeneous electromagnetic fields

宾夕法尼亚州立大学的Lasse Jensen得到了化学系化学理论、模型和计算方法计划的支持，该计划开发理论工具来描述位于金属纳米颗粒之间非常小间隙中的分子。在这些条件下，由于光在能隙中的强烈限制，光与分子之间的相互作用是复杂的。这个项目的重点是了解分子是如何由于光的限制而改变的。这些研究可能有助于理解分子如何在金属界面上组织，并应用于催化、能量转换和痕量分子检测。詹森教授开发了新的计算工具来描述测量分子与光相互作用的技术。这些工具通过并入现有的计算化学软件包向广大科学界传播。詹森教授使用交互式纳米光学模拟器，教育高中生、本科生和研究生了解我们的宏观世界和纳米尺度之间的区别。詹森教授正在开发一个多尺度模型来描述等离子体结中高度不均匀电磁场中分子的光谱。他的目标是了解高度受限领域中分子的光谱学，在那里，传统的远场光谱学的选择规则被打破。这样的计算工具提供了对这些高度受限的场如何改变分子响应以及局部环境的波动如何影响响应的微观理解。利用这个多尺度模型，Jensen教授和他的同事研究了空间受限电磁场、结的具体细节以及与附近分子的耦合如何影响分子的响应特性。这对于了解受限电磁场如何影响分子性质并最终影响其化学性质至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Lasse Jensen of the Pennsylvania State University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop theoretical tools for describing molecules situated in very small gaps between metal nanoparticles. Under these conditions the interactions between light and the molecule is complicated due to the strong confinement of light in the gap. The emphasis of this project is to understand how molecules are altered due to the confinement of light. The studies may provide an understanding of how molecules organize at metallic interfaces with applications in catalysis, energy conversion and trace molecule detection. Professor Jensen develops new computational tools to describe techniques that measure molecular interactions with light. These tools are disseminated to the broad scientific community through incorporation into available computational chemistry software packages. Using interactive nano-optics simulators, Professor Jensen educates high school, undergraduate and graduate students on the differences between our macroscopic world and the nanoscale. Professor Jensen is developing a multiscale model to describe the spectroscopy of molecules in highly inhomogeneous electromagnetic fields in plasmonic junctions. His goal is to understand the spectroscopy of molecules in highly confined fields where the selection rules known from traditional far-field spectroscopy breaks down. Such computational tools provide the microscopic understanding of how these highly confined fields modify the molecular response and how fluctuations in the local environment influences the response. Using this multiscale model, Professor Jensen and coworkers investigate how the response properties of molecules are affected by a spatially confined electromagnetic fields, the specific details of the junction, and the coupling to nearby molecules. This is essential for understanding how the confined electromagnetic fields influence the molecular properties and ultimately its chemistry.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.