Visualizing Photon Induced Dynamics in Polyatomic Molecules using Femtosecond Pump-Probe Laser Pulses

使用飞秒泵浦探测激光脉冲可视化多原子分子中的光子诱发动力学

• 批准号: 2306982
• 负责人: Nora Berrah
• 金额: $ 57万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2306982&HistoricalAwards=false
• 关键词: Visualizing; Photon; Induced; Dynamics; Polyatomic

The PI and her team will investigate the interaction of polyatomic molecules with light. Molecules are the primordial constituents of matter that surrounds us, from the air we breathe to the water we drink or the pharmaceutical drugs we take to cure diseases. Light plays a crucial role in humanity’s livelihood - for example, the rhodopsin molecules found in our eyes undergo an ultrafast transformation when exposed to light allowing us to see. This kind of transformation, which we call isomerization, impacts also technological applications such as molecular motors and re-writable optical memories. Other examples of the effect of light on cyclic molecules are the photo-synthesis of vitamin D3 in the skin or optoelectronic applications in optical switching and nanomechanical motors. These light-induced transformations of molecules hold a central role in physics, chemistry, and biology due to their importance in a wide variety of systems from the building blocks of proteins and antibiotics to industrial applications. Of crucial interest is how such molecules transform or break, after the absorption of light. This project, led by the PI and her team, is to investigate in detail these ultrafast photon-activated fundamental quantum mechanical mechanisms. This interdisciplinary research program integrates education at the undergraduate and graduate levels, strives to produce a diverse workforce and provides a comprehensive training in quantum science, programming, and ultrafast laser technology. This training benefits students and postdocs who are the next generation workforce in the STEM fields in academia and also in various industries. The PI’s research has, and will continue to train students and postdocs for several career tracks. Previous NSF funded students and postdocs trained with quantum mechanic, technical and computational skills in the PI’s research lab are now contributing to several areas of science and technology, in academia, national laboratories, defense, and industries such as financials, developing new laser technology and quantum optics. This research program has additional societal impact through its outreach and national mentoring activities of underrepresented groups. This NSF research program will investigate time-resolved ultrafast light-induced dynamics in polyatomic molecules in order to advance knowledge and understanding of non-adiabatic molecular dynamics due to their important role in fundamental physical and chemical processes. The PI and her team will contribute to the understanding of the conversion of photon energy from light into chemical energy via the physical and chemical mechanisms they will study. In particular, the PI’s team will examine the coupled electronic and nuclear dynamics during photo-induced chemical reactions with temporal resolution. Specifically, the team’s goal is to investigate, at the femtosecond timescale, how electronic rearrangement in molecules, subsequent to photon absorption, induces and effects nuclear motion and transformation in molecules. The team will examine in detail internal molecular energy conversion, atomic rearrangement in molecules, transformation of molecules through isomerization, molecular bond elongation, roaming molecular fragments that detach from the parent molecules but stay nearby and form new molecules, cyclic molecules opening, bond breaking, bond making and molecular fragmentation. The experiments will be conducted with Ultraviolet or Infrared laser pump-probe techniques. The resulting charged fragments will be detected using the coincidence technique of Cold-Target Recoil Ion Momentum Spectroscopy (COLTRIMS). The underlying photo-induced molecular dynamics will be revealed by ion-momentum imaging. This quasi-background free differential experimental imaging technique will provide new, detailed information on the aforementioned competing physical and chemical processes.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.

首席研究员和她的团队将研究多原子分子与光的相互作用。分子是我们周围物质的基本成分，从我们呼吸的空气到我们饮用的水或我们用来治疗疾病的药物，光起着至关重要的作用。在人类生计中发挥着重要作用 - 例如，我们眼睛中的视紫红质分子在暴露于光线时会发生超快的转变，使我们能够看到东西，这种转变（我们称之为异构化）也会影响分子马达和等技术应用。光对环状分子影响的其他例子包括皮肤中维生素 D3 的光合成或光开关和纳米机械电机中的光电应用，这些光诱导的分子转变在物理学中发挥着核心作用。由于它们在从蛋白质和抗生素的构建模块到工业应用的各种系统中的重要性，人们最感兴趣的是这些分子在吸收光后如何转变或断裂。 PI 和她的团队将详细研究这些超快光子激活的基本量子力学产生机制，这个跨学科研究项目整合了本科生和研究生的教育，致力于培养多元化的劳动力，并提供量子科学、编程、该培训使学生和博士后受益，他们是学术界和各行业 STEM 领域的下一代劳动力。PI 的研究已经并将继续为以前的 NSF 职业生涯提供培训。在 PI 研究实验室接受量子力学、技术和计算技能培训的受资助学生和博士后现在正在为学术界、国家实验室、国防和金融等行业的多个科学技术领域做出贡献，开发新的激光技术和量子光学该研究项目通过其对代表性不足群体的推广和国家指导活动产生了额外的社会影响。该研究项目将研究多原子分子中的时间分辨超快光诱导动力学，以增进对多原子分子的认识和理解。非绝热分子动力学由于其在基本物理和化学过程中的重要作用，将有助于理解光子能量通过他们将研究的物理和化学机制从光到化学能的转化。具体来说，该团队的目标是在飞秒时间尺度上研究光子吸收后分子中的电子重排如何引发和影响。核该团队将详细研究分子内部能量转换、分子中的原子重排、通过异构化进行的分子转化、分子键伸长、与母体分子分离但留在附近并形成新分子的漫游分子碎片、循环。分子打开、键断裂、键形成和分子碎裂将使用紫外或红外激光泵浦探针技术进行，并使用冷目标反冲离子符合技术来检测所产生的带电碎片。动量光谱 (COLTRIMS)。离子动量成像将揭示潜在的光诱导分子动力学，该成像将提供有关所讨论的竞争物理和化学过程的新的详细信息。该奖项技术反映了 NSF 的技术。法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。