权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Coherent Control of Cold Collision by Preparing Molecular Eigenstates Using Stark-Induced Adiabatic Passage

利用斯塔克诱导绝热通道制备分子本征态来相干控制冷碰撞

基本信息

批准号：
2110256
负责人：
Richard Zare
金额：
$ 46.36万
依托单位：
Stanford University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2110256&HistoricalAwards=false
关键词：
Coherent Control Cold Collision Preparing

项目摘要

General audience abstract:This project focuses on developing a comprehensive understanding of the quantum mechanical processes that drive molecular interactions including chemical reactions at the most fundamental level. The main goal of this research is to explore the character of quantum systems and improve our ability to manipulate them, which is of great importance in various applications including realization of a quantum computer. The research team will carry out low energy (cold) collision experiments with molecules prepared in well-defined quantum states. By correlating the quantum states of the incoming particles with those of the outgoing particles they will explore the quantum mechanical interactions involved in making and breaking chemical bonds. This research combines cutting edge quantum optical techniques and expertise in laser spectroscopy with state-resolved collision dynamics using a supersonically expanded molecular beam. The graduate students involved in this project will learn the technical skills needed for multiphoton laser spectroscopy using vacuum ultraviolet laser pulses, quantum state preparation using sophisticated single-mode pulsed laser systems, and manipulation of a supersonic beam. Additionally, the research team will design a high resolution mass spectrometer to resolve the scattering angular distribution in cold collisions. This comprehensive training in broad areas of quantum physics and chemistry will help to prepare the students to be leaders in improving the science and technology of tomorrow. Technical audience abstract:To understand the quantum mechanical processes involved in chemical reactions, it is essential to find a direct correspondence between experimental measurements and theoretical calculations. To achieve this goal, experimentalists need to select theoretically tractable molecules like H2 (N2, CO, etc.), which are also of relevance to current science. The researchers will prepare diatomic molecules in high vibrational states using a coherent optical technique called multi-step Stark-induced adiabatic Raman passage (multi-step SARP). Multi-step SARP is a generalization of the SARP process developed earlier by this research group, which can pump a large ensemble of H2 molecules to a variety of vibrationally excited levels. Multi-step SARP will combine two or more SARP processes to achieve near complete population transfer to a very highly vibrationally excited level. The researchers have shown theoretically that by combining several Stokes pulses on the wing of a stronger pump pulse it is possible to reach very high vibrational states. Long term prospects for this technique include preparing the highest vibrational level of H2 and even reaching the vibrational dissociation continuum, generating a pair of entangled loosely bound H atoms. These exotic quantum systems will allow the researchers to overcome the reaction barrier in cold and ultracold collisions and test fundamental quantum physics principles, such as interference in collision. The first goal of the project is to set up the multi-step SARP experiment and demonstrate the preparation of very high vibrationally excited levels of H2. Selection of the laser polarization used in the multi-step SARP will permit control of the alignment of the bond axis of the highly vibrationally excited molecules. Excitation of very high vibrational states using a two-step SARP process will be a major leap forward in the study of cold molecular collisions. Once prepared the researchers will carry out cold scattering experiments on the four-center reaction H2 + D2 →2HD in a supersonically expanded mixed beam of H2 and D2. The collision dynamics of highly vibrationally excited H2 molecules are of immense interest for understanding and modelling the physics and chemistry of the interstellar medium. Additionally, high-lying vibrational levels of H2 are considered essential to the efficient generation of H- beams by dissociative attachment of low energy electrons, which has important applications in igniting a fusion reactor.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.

一般观众摘要：该项目的重点是发展的量子力学过程，驱动分子相互作用，包括在最基本的水平上的化学反应的全面理解。本研究的主要目标是探索量子系统的特性，提高我们操纵它们的能力，这在包括实现量子计算机在内的各种应用中具有重要意义。该研究小组将对在明确定义的量子态中制备的分子进行低能（冷）碰撞实验。通过将入射粒子的量子态与出射粒子的量子态相关联，他们将探索建立和破坏化学键所涉及的量子力学相互作用。这项研究结合了尖端的量子光学技术和激光光谱学的专业知识，使用超音速扩展分子束进行状态分辨碰撞动力学。参与该项目的研究生将学习使用真空紫外激光脉冲进行多光子激光光谱学所需的技术技能，使用复杂的单模脉冲激光系统进行量子态制备，以及操纵超声光束。此外，研究小组将设计一个高分辨率质谱仪，以解决冷碰撞中的散射角分布。在量子物理和化学的广泛领域的全面培训将有助于培养学生成为提高未来科学和技术的领导者。技术观众摘要：为了理解化学反应中涉及的量子力学过程，必须找到实验测量和理论计算之间的直接对应关系。为了实现这一目标，实验者需要选择理论上易于处理的分子，如H2（N2，CO等），这也与当前的科学有关。研究人员将使用称为多步斯塔克诱导绝热拉曼通道（多步SARP）的相干光学技术制备高振动态的双原子分子。多步SARP是该研究小组早期开发的SARP过程的概括，它可以将大量H2分子泵送到各种振动激发能级。多步SARP将联合收割机结合两个或多个SARP过程，以实现接近完全的布居转移到非常高的振动激发水平。研究人员已经从理论上证明，通过在更强的泵浦脉冲的机翼上组合几个斯托克斯脉冲，可以达到非常高的振动状态。该技术的长期前景包括制备H2的最高振动能级，甚至达到振动解离连续谱，产生一对纠缠的松散结合的H原子。这些奇异的量子系统将使研究人员能够克服冷和超冷碰撞中的反应障碍，并测试基本的量子物理学原理，例如碰撞中的干涉。该项目的第一个目标是建立多步SARP实验，并演示非常高的振动激发水平的H2的制备。在多步SARP中使用的激光偏振的选择将允许控制高度振动激发的分子的键轴的对准。利用两步SARP过程激发极高振动态将是冷分子碰撞研究的一个重大飞跃。一旦准备就绪，研究人员将在H2和D2的超音速扩展混合束中对四中心反应H2 + D2 → 2 HD进行冷散射实验。高度振动激发的H2分子的碰撞动力学对于理解和模拟星际介质的物理和化学具有巨大的意义。此外，H2的高振动能级被认为是通过低能电子的解离附着有效产生H-束的关键，这在点燃聚变反应堆中具有重要的应用。该奖项反映了NSF的法定使命，并被认为值得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来支持。