Studying Correlated Electron Dynamics in Molecules and Materials with Isolated Attosecond Pulses

用孤立阿秒脉冲研究分子和材料中的相关电子动力学

• 批准号: 1505556
• 负责人: Arvinder Sandhu
• 金额: $ 32.18万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505556&HistoricalAwards=false
• 关键词: Studying; Correlated; Electron; Dynamics; Molecules

Electrons play a fundamental role in most natural and laboratory phenomena. These elementary particles are extremely light and agile--they can move inside atoms, molecules and materials on the timescale of "attoseconds," which is a billionth of a billionth of a second. To understand the functioning of physical, chemical, and biological processes, it is important to be able to resolve and control the underlying fast electronic motion. Newly devised attosecond techniques provides exactly such an opportunity, using light pulses to strobe the dynamics of electrons. However, most initial studies in this field have been conducted on simple systems like atoms and small molecules. The researchers supported by this program will develop and extend attosecond techniques to the study of complex molecules and materials, where one or more electrons are interacting with each other. Success along these directions will open up opportunities for direct investigation of many biochemical and nanomaterial processes relevant for light harvesting and energy storage. The proposed program will therefore advance the state of science by building bridges between the field of physics, and those of chemistry, biology, and material sciences. The project will also train the next generation of scientists belonging to diverse backgrounds in this emerging and interdisciplinary research field.Electronic correlation often dominates the excitation and relaxation dynamics of photo-excited molecules and nanomaterials, manifesting itself in the energy and charge redistribution mechanisms in important natural and laboratory processes, such as photosynthesis, repair and damage or DNA, energy storage at molecule-semiconductor interfaces etc. This research project aims at the investigation of correlation-driven physical and chemical phenomena using various types of ultrafast spectroscopy. The high temporal resolution required for these studies will be achieved through the generation of isolated attosecond pulses using double optical gating or similar schemes. The scientific objectives of this program will be to: (1) investigate coherent charge migration dynamics in polyatomic molecules, such as those consisting of a phenyl group, (2) study the coherence in electron wavepacket dynamics and the origin of decoherence mechanisms, and (3) probe the generation and dynamics of high energy excitons in carbon nanomaterials (e.g. graphene). These objectives will be achieved while training graduate and undergraduate students in the field of attosecond physics. Two powerful experimental techniques will be utilized in the proposed measurements: velocity map imaging and attosecond transient absorption. The investigations outlined in the proposal will provide the building blocks for developing a better understanding of the inner-workings of natural and practically relevant phenomena. Collaborations with theorists will play crucial role in the interpretation of results obtained in this unchartered territory, potentially leading to the development of new theoretical models.

电子在大多数自然和实验室现象中起着重要作用。 这些基本粒子非常轻和敏捷-它们可以在“阿秒”的时间尺度上在原子，分子和材料中移动，这是十亿分之一秒的十亿分之一。 为了理解物理、化学和生物过程的功能，重要的是能够解决和控制潜在的快速电子运动。新发明的阿秒技术正好提供了这样一个机会，它使用光脉冲来选通电子的动力学。 然而，该领域的大多数初步研究都是在原子和小分子等简单系统上进行的。该计划支持的研究人员将开发和扩展阿秒技术，以研究复杂的分子和材料，其中一个或多个电子相互作用。沿着这些方向的成功将为直接研究与光捕获和能量存储相关的许多生物化学和纳米材料过程开辟机会。因此，拟议的计划将通过在物理学领域与化学，生物学和材料科学领域之间建立桥梁来推进科学的发展。 该项目还将培养属于这一新兴和跨学科研究领域的不同背景的下一代科学家。电子相关往往主导着光激发分子和纳米材料的激发和弛豫动力学，表现在重要的自然和实验室过程中的能量和电荷重新分配机制，如光合作用，修复和损伤或DNA，本研究项目旨在利用各种类型的超快光谱研究相关驱动的物理和化学现象。这些研究所需的高时间分辨率将通过使用双光门或类似方案产生孤立的阿秒脉冲来实现。该计划的科学目标是：（1）研究多原子分子中的相干电荷迁移动力学，例如由苯基组成的分子，（2）研究电子波包动力学的相干性和退相干机制的起源，以及（3）探测碳纳米材料（例如石墨烯）中高能激子的产生和动力学。这些目标将在培养阿秒物理学领域的研究生和本科生时实现。两个强大的实验技术将被利用在拟议的测量：速度图成像和阿秒瞬态吸收。提案中概述的调查将为更好地了解自然和实际相关现象的内部运作提供基础。与理论家的合作将在解释这一未知领域所获得的结果方面发挥至关重要的作用，可能导致新理论模型的发展。