Beam Deflection Studies of Cold Molecules and Complexes Entrapped in Helium Nanodroplets: Permanent, Metastable, and Laser-Induced Electric and Magnetic Dipole Moments

氦纳米液滴中捕获的冷分子和复合物的光束偏转研究：永久、亚稳态和激光诱导的电偶极矩和磁偶极矩

• 批准号: 2153255
• 负责人: Vitaly Kresin
• 金额: $ 50.26万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2153255&HistoricalAwards=false
• 关键词: Beam; Deflection; Studies; Cold; Molecules

In this project, supported by the Chemical Structure, Dynamics, and Mechanisms (CSDM-A) Program of the Division of Chemistry, Prof. Vitaly Kresin’s group at the University of Southern California will study the distributions of electrical charges and magnetic currents within extremely cold molecules carried by a beam of nanoscale droplets of superfluid helium. These distributions reveal information about molecular structure, motion, and bonding. The nanodroplets will pass through an externally applied electric or magnetic field, and the field-induced deflection of their trajectories will be measured. The study will encompass the electric and magnetic structure of biological molecules, atomic and molecular complexes, “molecular magnets,” and other systems that are impractical to accurately measure, or even synthesize, by other means. The project also will demonstrate steering of a molecular reaction by an external electric field and detecting the switching of the electric polarity of a molecule by a tunable laser. The project will lead to new knowledge that has broad relevance to basic research and applications ranging from protein formation to ultracold chemistry, spintronics to organic synthesis, and atmospheric chemistry to quantum information science. Graduate and undergraduate students will be mentored in a highly interdisciplinary research field and engage in science fairs and school outreach programs. A collaboration between the project and an undergraduate laboratory course in combinatorial chemistry will be established.The nanodroplets, formed via supersonic expansion of helium gas, will embed molecules, atoms, or clusters from vapor in pick-up cells, and then traverse a strong inhomogeneous electric or magnetic field. This field will orient the ultracold polar impurities and exert an intense deflecting force, resulting in a measurable deviation of the beam, thus enabling direct readout of the electric or magnetic dipole moment of the molecule or complex. This technique will be applied to hydrogen peroxide clusters, amino acid dimers and dipeptides, high-spin alkali dimers, and molecular magnets. Furthermore, the project will demonstrate the assembly of pre-oriented molecules, and deflection-based action spectroscopy of photochromic molecules.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.

在这个项目中，由化学系的化学结构，动力学和机制（CSDM-A）计划支持，南加州大学的Vitaly Kresin教授的小组将研究超流氦纳米级液滴束携带的极冷分子内的电荷和磁流分布。这些分布揭示了分子结构、运动和成键的信息。纳米液滴将通过外部施加的电场或磁场，并测量其轨迹的场致偏转。该研究将包括生物分子，原子和分子复合物，“分子磁体”和其他系统的电磁结构，这些系统无法通过其他方法准确测量或合成。该项目还将演示通过外部电场控制分子反应，并通过可调谐激光检测分子电极性的切换。该项目将带来与基础研究和应用广泛相关的新知识，从蛋白质形成到超冷化学，从自旋电子学到有机合成，从大气化学到量子信息科学。研究生和本科生将在一个高度跨学科的研究领域进行指导，并参加科学博览会和学校推广计划。该项目将与组合化学的本科实验室课程建立合作关系。通过氦气的超音速膨胀形成的纳米液滴将从蒸汽中嵌入分子、原子或团簇，然后穿过强不均匀的电场或磁场。该场将定向超冷极性杂质并施加强烈的偏转力，导致光束的可测量偏差，从而能够直接读出分子或复合物的电或磁偶极矩。该技术将应用于过氧化氢簇，氨基酸二聚体和二肽，高自旋碱二聚体和分子磁体。此外，该项目还将展示预取向分子的组装，以及光致变色分子基于偏转的作用光谱。该奖项反映了NSF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。

项目成果

Probing the presence and absence of metal-fullerene electron transfer reactions in helium nanodroplets by deflection measurements

通过偏转测量探测氦纳米液滴中金属-富勒烯电子转移反应的存在与否

• DOI: 10.1039/d2cp00751g
• 发表时间: 2022
• 期刊: Physical Chemistry Chemical Physics
• 影响因子: 3.3
• 作者: Niman, John W.;Kamerin, Benjamin S.;Villers, Thomas H.;Linker, Thomas M.;Nakano, Aiichiro;Kresin, Vitaly V.
• 通讯作者: Kresin, Vitaly V.