Non-Adiabatic Photonic Processes in Molecular Plasma

分子等离子体中的非绝热光子过程

• 批准号: 2110279
• 负责人: Viatcheslav Kokoouline
• 金额: $ 23.11万
• 依托单位: The University of Central Florida Board of Trustees
• 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=2110279&HistoricalAwards=false
• 关键词: Non; Adiabatic; Photonic; Processes; Molecular

When light propagates through a gas of molecules, such as air, it can remove electrons from the molecules, the processes known as photoionization. This process and the one reverse to it, recombination, play an extremely important role in modern technology, in atmospheric sciences, in astrophysics, and many other fields of research. This is the reason why there is a growing need for theoretical methods able to interpret and predict behavior of molecular gases under ionizing radiation. Although there has been significant progress in a theoretical description of atomic photoionization, the situation with theory in molecular gases is far from being satisfactory. A reliable theoretical description of ionization in molecular gases is complicated due to the complex quantum-mechanical structure of molecules. The main science question of the present project is whether theory can describe photoionization of diatomic molecules, such as those present in air, especially in situations where experimental data do not exist. The major goal of the project is to develop theoretical methods able to model photoionization of linear molecules (and negatively charged molecular ions). An important broader impact of the proposed research is the development of a web-based platform and a related methodology to teach Quantum Mechanics in studio mode-like classes. The platform allows students and their instructors to perform numerical experiments for all main concepts of Quantum Mechanics.The photoionization spectrum of molecular nitrogen, N2, will be computed for photon energies above the ionization threshold from the ground vibronic state. Transition dipole moment functions between the N2 ground electronic state and three lowest electronic states of N2+ will be computed and made available to the community. Vibrational and rotation motion of N2 and N2+ will be accounted for as well as non-adiabatic coupling between electronic states of the N2+ ion. For this purpose, the multichannel quantum defect theory (MQDT) and rovibronic frame transformation will be employed. Using the developed theoretical model of photoionization in N2, cavity-free lasing of N2+, observed in several experimental groups, will be studied. The second objective of the project is to study time-delay and thresholds laws in photodetachment. The PI will model and study photodetachment spectra of molecular anions, taking into account non-adiabatic effects, interaction of the photoelectron with rotational and vibrational motion of the molecule. The study will include the dependence of main features in the spectra (such as resonances, threshold behavior...) on the dipole moment of the molecule, the rotational and vibrational structure of the molecule, and the presence of one or several dipolar electronic states. The study will be performed using a FEM (Finite-element method) code able to treat collisions of electrons with linear molecules, solving the Schrodinger equation for electronic and rovibrational motion of the target at the same time. The time-delay in the photodetachment process will be considered and a scheme to observe the time-delay in photodetachment experiments will be developed.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.

当光通过分子气体（如空气）传播时，它可以从分子中去除电子，这一过程称为光电离。这个过程和与之相反的过程，即复合，在现代技术、大气科学、天体物理学和许多其他研究领域中起着极其重要的作用。这就是为什么越来越需要能够解释和预测电离辐射下分子气体行为的理论方法的原因。虽然原子光电离的理论研究已经取得了很大的进展，但分子气体的理论研究还远远不能令人满意。由于分子的复杂量子力学结构，分子气体电离的可靠理论描述是复杂的。本项目的主要科学问题是理论是否可以描述双原子分子的光致电离，例如空气中的双原子分子，特别是在实验数据不存在的情况下。该项目的主要目标是开发能够模拟线性分子（和带负电荷的分子离子）的光电离的理论方法。拟议的研究的一个重要的更广泛的影响是开发一个基于网络的平台和相关的方法来教量子力学在工作室模式类类。该平台允许学生和他们的教师对量子力学的所有主要概念进行数值实验。对于高于基态振动态电离阈值的光子能量，将计算分子氮N2的光电离光谱。N2基态电子态和N2+的三个最低电子态之间的跃迁偶极矩函数将被计算并提供给社区。振动和旋转运动的N2和N2+将占以及N2+离子的电子状态之间的非绝热耦合。为此，将采用多通道量子亏损理论（MQDT）和旋转振动坐标系变换。利用发展的N2光电离理论模型，研究了在几个实验组中观察到的N2+的无腔激光。本计画的第二个目标是研究光剥离的时间延迟与阈值规律。PI将模拟和研究分子阴离子的光剥离光谱，考虑到非绝热效应，光电子与分子的旋转和振动运动的相互作用。该研究将包括光谱中主要特征的依赖性（如共振，阈值行为......）取决于分子的偶极矩、分子的旋转和振动结构以及一个或多个偶极电子态的存在。该研究将使用能够处理电子与线性分子碰撞的FEM（有限元法）代码进行，同时求解目标电子和振转运动的薛定谔方程。在光剥离过程中的时间延迟将被考虑，并将制定一个计划，以观察在光剥离实验中的时间延迟。这个奖项反映了NSF的法定使命，并已被认为是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的支持。

项目成果

Radiative electron attachment to rotating C3N through dipole-bound states

辐射电子通过偶极束缚态附着到旋转的 C3N

• DOI: 10.1103/physreva.107.043117
• 发表时间: 2023
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: Forer, Joshua;Kokoouline, Viatcheslav;Stoecklin, Thierry
• 通讯作者: Stoecklin, Thierry

Electron scattering on molecular nitrogen: common gas, uncommon cross sections

• DOI: 10.1140/epjd/s10053-023-00687-5
• 发表时间: 2023-06
• 期刊: The European Physical Journal D
• 作者: Mi-Young Song;Hyuck Cho;G. Karwasz;V. Kokoouline;J. Tennyson

Ozone Formation in Ternary Collisions: Theory and Experiment Reconciled

三元碰撞中臭氧的形成：理论与实验的协调

• DOI: 10.1103/physrevlett.128.108501
• 发表时间: 2022
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Mirahmadi, Marjan;Pérez-Ríos, Jesús;Egorov, Oleg;Tyuterev, Vladimir;Kokoouline, Viatcheslav
• 通讯作者: Kokoouline, Viatcheslav