Laser Control of Quantum Evolution in Molecules

分子量子演化的激光控制

• 批准号: 1806145
• 负责人: Philip Bucksbaum
• 金额: $ 140万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1806145&HistoricalAwards=false
• 关键词: Laser; Control; Quantum; Evolution; Molecules

The motion of electrons and protons inside molecules when they are subjected to strong forces is a fundamental issue in molecular and chemical science. Understanding and controlling this internal motion is important: For example, proton motion does much of the work in organic chemistry, energy storage, and biomedicine, therefore controlling proton motion with external forces may be useful in future implementations of chemical synthesis or quantum computing; or even for splitting water to make hydrogen fuel. This NSF program will explore new ways to create and control the motion of protons and electrons inside molecules using external laser fields in the laboratory. The laser field strengths must be large enough to overcome the internal fields that hold molecules together, on the order of volts per Angstrom; and they must be able to pulse on and off in well under a hundredth of a trillionth of a second as well, to keep up with the natural pace of movement inside molecules. Research using these laser tools will test basic models of molecular transformations, such as conjectures that there are special atomic geometries where molecules become especially susceptible to control by outside forces. The molecules to be tested are water and acetylene, both proton-rich building-blocks for many chemical processes. This research will also provide training for students and postdocs, and thus prepare them to contribute technical talents that are needed to support the nation's economy and security in the coming century. Intramolecular motion is one of the core issues in molecular physics, and the key to many important physical and chemical processes such as chemical synthesis and energy production. This activity explores how ultrafast laser-induced strong field interactions can change the motion of atoms in molecules and therefore alter the path of chemical change. These paths are complicated in part because the motion of every atom in a molecule generally affects every other atom. The result is that motion takes place in a high-dimensional space: three internal dimensions for a simple three-atom molecule like water; but three additional dimensions for every additional atom in the molecule. The high-dimensional topology of this space is difficult to visualize and highly non-intuitive. It leads to special locations in this molecular landscape -- seams or surfaces structures embedded in the higher dimensional space -- where the interatomic bonds can rearrange without any energy penalty. Here the objective is to understand how high-dimensional features in coupled atomic motion can be altered by strong laser fields to enhance, suppress, or modify atomic rearrangement, rapid ionization, multiple ionization, and even Coulomb explosions. This tests a hypothesis that external strong fields coupled to atomic motion can control and redirect these natural processes. Water and acetylene have been selected for study because their internal motion is dominated by hydrogen atoms, which move more rapidly because of the low mass of their proton nuclei. This enhances the effects under study. The investigations use infrared, ultraviolet, and vacuum ultraviolet coherent laser fields to both excite and control these molecular systems. Results of the excitation and the control are measured by recording the velocities of all of the molecular constituents directly, either by allowing the molecules to fall apart or by forcing them apart with a laser-produced Coulomb explosion. Understanding molecular behavior in external fields has relevance for many practical applications areas, including catalysis, proton medical therapy and photo-initiated hydrogenase 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.

电子和质子在分子内部受到强作用力时的运动是分子和化学科学中的一个基本问题。理解和控制这种内部运动是很重要的：例如，质子运动在有机化学、能量储存和生物医学中起着很大的作用，因此用外力控制质子运动可能在未来的化学合成或量子计算中有用;甚至可以用于分解水以制造氢燃料。这个NSF计划将探索在实验室中使用外部激光场来创建和控制分子内部质子和电子运动的新方法。激光场强度必须足够大，以克服将分子结合在一起的内部场，大约为每埃伏特;它们必须能够在万亿分之一秒的百分之一内脉冲开启和关闭，以跟上分子内部运动的自然速度。使用这些激光工具的研究将测试分子转变的基本模型，例如存在特殊原子几何形状的假设，其中分子变得特别容易受到外力的控制。被测试的分子是水和乙炔，它们都是许多化学过程中富含质子的组成部分。这项研究还将为学生和博士后提供培训，从而使他们为支持下世纪国家经济和安全所需的技术人才做好准备。分子内运动是分子物理的核心问题之一，是化学合成、能量产生等许多重要物理化学过程的关键。这项活动探索了超快激光诱导的强场相互作用如何改变分子中原子的运动，从而改变化学变化的路径。这些路径是复杂的，部分原因是分子中每个原子的运动通常会影响其他原子。其结果是运动发生在一个高维空间中：对于一个简单的三原子分子，如水，有三个内部维度;但对于分子中每增加一个原子，有三个额外的维度。这个空间的高维拓扑很难可视化，而且非常不直观。它导致了分子景观中的特殊位置--嵌入高维空间的接缝或表面结构--在那里原子间的键可以重新排列而不需要任何能量损失。在这里，我们的目标是了解如何在耦合原子运动的高维特征可以改变强激光场，以增强，抑制或修改原子重排，快速电离，多重电离，甚至库仑爆炸。这验证了一个假设，即与原子运动耦合的外部强场可以控制和重定向这些自然过程。选择水和乙炔进行研究是因为它们的内部运动由氢原子主导，氢原子由于质子核的质量较低而运动得更快。这增强了所研究的效果。研究使用红外，紫外和真空紫外相干激光场来激发和控制这些分子系统。激发和控制的结果是通过直接记录所有分子组分的速度来测量的，或者通过允许分子分裂，或者通过用激光产生的库仑爆炸迫使它们分开。理解外场中的分子行为与许多实际应用领域相关，包括催化、质子医学治疗和光引发氢化酶化学。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

Strong-Field Enhanced Ionization of Water using 6-fs Pulse Pairs

使用 6-fs 脉冲对强场增强水电离

• 发表时间: 2022
• 期刊: International Conference on Ultrafast Phenomena 2022
• 作者: Howard, A.H.;Britton, M.;Reynolds, J.: Gabalski;Forbes, R.;Cheng, C.;Weinacht, T.;Bucksbaum, P.H.
• 通讯作者: Bucksbaum, P.H.

Filming and viewing ultrafast motion inside molecules: What do we see and what can we learn?

拍摄和观察分子内部的超快运动：我们看到了什么以及我们能学到什么？

• 发表时间: 2023
• 期刊: Bulletin of the American Physical Society
• 作者: Bucksbaum, P.

Wavelength dependence in strong field ionization of water

水强场电离的波长依赖性

• 发表时间: 2021
• 期刊: Molecular and Optical Physics
• 作者: Britton, Mathew;McCracken, Gregory A.;Howard, Andrew J.;Peard, Nolan;Forbes, Ruaridh;Bucksbaum, Philip H.
• 通讯作者: Bucksbaum, Philip H.

Strong-field ionization of water. II. Electronic and nuclear dynamics en route to double ionization

• DOI: 10.1103/physreva.104.023108
• 发表时间: 2021-08-23
• 期刊: PHYSICAL REVIEW A
• 影响因子: 2.9
• 作者: Cheng, Chuan;Streeter, Zachary L.;Forbes, Ruaridh
• 通讯作者: Forbes, Ruaridh

Ultrafast Molecular Imaging Using 4-Fold Covariance: Coincidence Insight with Covariance Speed

使用 4 倍协方差的超快分子成像：协方差速度的符合洞察力

• DOI: 10.1364/up.2022.tu4a.40
• 发表时间: 2022
• 期刊: The International Conference on Ultrafast Phenomena (UP
• 作者: Cheng, Chuan;Frasinski, Leszek J.;Moğol, Gönenç;Allum, Felix;Howard, Andrew J.;Bucksbaum, Philip H.;Brouard, Mark;Forbes, Ruaridh;Weinacht, Thomas
• 通讯作者: Weinacht, Thomas