Exploring Strong Field Electronic and Molecular Dynamics

韦恩州立大学的H·伯恩哈德·施莱格尔教授得到了化学部理论、模型和计算方法项目的支持。他研究强激光脉冲与分子的相互作用，以研究在很短的时间尺度(阿秒，或千亿分之一秒)内发生的化学反应。这项研究本质上是理论和计算的，是在与实验科学家密切合作的情况下进行的，他们正在激光实验室测试这些理论的预测。施莱格尔博士的研究揭示了在被称为电子动力学的化学反应过程中，如何利用短而强烈的脉冲发出的光来跟踪分子中电子的运动。这一基础性研究的结果可以提供有关化学反应的各个步骤及其机理的详细信息，这有助于提高化学过程的效率。他举办研讨会，指导学生研究人员如何利用计算化学软件。科学界可以通过施莱格尔博士的网站获得在该项目期间开发的计算机软件，并将其整合到通用量子化学计算机代码中。分子对强激光场的响应包括时间尺度为几百阿秒的电子动力学和几飞秒甚至更长时间的分子动力学。目前正在为这两种时间尺度制定模拟这些相互作用的方法。采用实空间复吸收势含时组态相互作用方法(TDCI-CAP)和含时密度泛函理论实时积分方法(RT-TDDFT)研究了强激光场中分子的电子动力学和电离。机器学习正在进行测试，以根据轨道能量、电离势以及分子轨道、静电势和电场梯度的形状来预测强场电离的角度相关性。Born-Oppenheimer、扩展拉格朗日和Ehrenfest动力学被用来模拟超短、强烈的中红外激光脉冲对阳离子的异构化和裂解。激发态在强场异构化和碎裂反应中的参与将用非绝热分子动力学进行研究。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Professor H. Bernhard Schlegel of Wayne State University is supported by an award from the Theory, Models and Computational Methods program within the Chemistry Division. He studies the interaction of intense laser light pulses with molecules to investigate chemical reactions that occur over a very short time scale (attoseconds, or quadrillionths of a second). The research is theoretical and computational in nature and is being carried out in close collaboration with experimental scientists who are testing the predictions of these theories in laser laboratories. Dr. Schlegel's investigations are revealing how light delivered in short, intense pulses can be used to follow the movement of electrons in molecules during chemical reactions, called electron dynamics. Results of this fundamental study can provide details about the individual steps involved in a chemical reaction, its mechanism, which can aid in making chemical processes more efficient. He conducts workshops to instruct student researchers on how to utilize computational chemistry software. The computer software developed during the project is available to the scientific community through Dr. Schlegel's website and is incorporated into general-purpose quantum chemistry computer codes. The response of molecules to intense laser fields involves electron dynamics on a time scale as short as few hundreds of attoseconds and molecular dynamics at times of a few femtoseconds and longer. Methodologies to simulate these interactions are being developed for both time scales. Time-dependent configuration interaction methods with real space complex absorbing potentials (TDCI-CAP) and real-time integration of time-dependent density functional theory (rt-TDDFT) are used to investigate electron dynamics and ionization of molecules in strong laser fields. Machine learning is being tested for predicting the angular dependence of strong field ionization from orbital energies, ionization potentials and the shapes of molecular orbitals, electrostatic potentials and electric field gradients. Born-Oppenheimer, extended Lagrangian and Ehrenfest dynamics are being used to simulate isomerization and fragmentation in cations by ultra-short, intense mid-infrared laser pulses. The involvement of excited states in strong field isomerization and fragmentation reactions is to be investigated with non-adiabatic molecular dynamics.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.