AQuA DIP: Advanced Quantum Approaches to Double Ionisation Processes

AQuA DIP：双电离过程的先进量子方法

基本信息

批准号：
EP/T019530/1
负责人：
Andrew Brown
金额：
$ 110.33万
依托单位：
Queen's University Belfast
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT019530%2F1
关键词：
AQuA DIP Advanced Quantum Approaches

项目摘要

In order to 'view' electrons in the atom, we need to be able to describe their motion on a time-scale comparable to the interactions themselves. This is akin to taking a photograph- the faster an object is moving, the shorter the exposure time required to capture it. In atomic and optical physics we effectively use ultrashort 'camera' flashes (laser pulses) to image electrons in motion. While this field of attosecond physics (1 attosecond = 1 billionth of a billionth of a second) is well established, the theoretical description and computational models of the underlying mechanisms are relatively underdeveloped.We are particularly interested, in this project, in double-ionisation processes: mechanisms whereby two electrons escape from an atomic target. There is a two-fold technological motivation for this interest. Firstly, X-ray Free-Electron Laser systems (or XFELs for short) allow the delivery of massively energetic radiation capable of multiply ionising a target with just one or two photons. Secondly, table-top sources capable of delivering short, intense laser pulses in the visible to mid-infrared regime drive dynamics in what is known as the 'strong-field' regime, where the electric field of the laser is strong enough to distort the potential well binding the electrons to the target, allowing them to escape. Processes such as 'non-sequential double ionisation' (NSDI) or 'resonant excitation and subsequent ionisation' (RESI) are fascinating because they depend not only on the characteristics of the laser field, but also on the detailed and complex interactions taking place between the many electrons.Because of this complexity, there is a dearth of methods capable of providing theoretical insight to these processes. Computational or analytical methods tend to specialise in one particular regime (either XFEL or Strong-field) and even then, many choose to focus on the laser-driven dynamics, ignoring the electronic-interaction part of the picture. For this reason, in this project we will develop three complementary methods to address double-ionisation dynamics in atoms. One is the R-matrix with time-dependence, or 'RMT' approach, which will use techniques of high-performance computing to break the immensely complex calculation into smaller parts, solved in parallel by many thousands of processors. The second is the Coulomb Quantum Strong Field Approximation, or 'CQSFA', which is an analytical technique based on electron trajectories. This lends enhanced interpretational power to the CQSFA, because it provides a clear physical picture of the dynamics, which can sometimes be obscured in the full, quantum-wavefunction picture employed by RMT. The third approach we will develop is a hybrid of RMT and CQSFA: giving the best of both: a sophisticated and accurate treatment of the core dynamics (the behaviour of the atomic target in the laser field) and a clear interpretation of the continuum dynamics (the behaviour of the ionised electrons). Having developed these three, complementary tools we will apply them to problems of double ionisation in XFEL and strong-field laser pulses. In particular we will address those processes which contain a strong influence from both the laser field and the quantum mechanical behaviour of the target, as this is the regime largely unserviced by current methodology. Hence we will perform studies of NSDI and RESI, as well as core-ionization followed by Auger decay and single photon double ionization driven by XFEL light. Understanding these mechanisms will inform our understanding of all light-mediated electronic processes, including important biological actions such as photosynthesis and the operation of the eye. The ultimate goal of attoscience is to control these processes and realise the potential benefits for society. Tools, such as those developed in this project, may prove to be incomparably valuable in this pursuit.

为了在原子中“查看”电子，我们需要能够描述它们在与相互作用本身相当的时间尺度上的运动。这类似于拍摄照片 - 物体移动的速度越快，捕获它所需的曝光时间就越短。在原子和光学物理学中，我们有效地使用Ultrashort“相机”闪光灯（激光脉冲）来形象运动。尽管已经确定了这个Attosecond物理学领域（1亿分之一的十亿分之一），但基本机制的理论描述和计算模型相对欠发达。我们在这个项目中特别感兴趣，在此项目中，双电离的过程：两种电子设置逃脱了两个电子目标。这一兴趣有两个技术动机。首先，X射线自由电子激光系统（或Xfels的简短）允许传递能够仅用一个或两个光子将目标乘以目标的巨大辐射。其次，能够在可见的中间粉红外驱动动力学中传递短而强烈的激光脉冲的桌面源，在所谓的“强场”状态下，激光的电场足够强，足以使电势将电子结合到目标上，从而使它们能够逃脱。诸如“非顺序双电离”（NSDI）或“谐音激发和随后的电离”（RESI）之类的过程令人着迷，因为它们不仅取决于激光领域的特征，还取决于在许多电子之间进行的详细且复杂的互动。在许多电子中进行了这种复杂性，因此能够实现了能力的方法，这些过程始终是一种能力的方法。计算或分析方法倾向于专门研究一种特定的制度（XFEL或强场），即使这样，许多人还是选择专注于激光驱动的动力学，而忽略了图片的电子相互作用部分。因此，在此项目中，我们将开发三种补充方法来解决原子中的双峰动态。一种是带有时间依赖性或“ RMT”方法的R-Matrix，它将使用高性能计算技术将非常复杂的计算分解为较小的部分，并通过数千个处理器并行解决。第二个是库仑量子强场近似或“ CQSFA”，这是一种基于电子轨迹的分析技术。这为CQSFA提供了增强的解释能力，因为它提供了清晰的动态物理图片，有时可以在RMT使用的完整，量子波功能的图片中遮盖。我们将开发的第三种方法是RMT和CQSFA的杂种：给予两者兼而有之：对核心动力学（激光场中原子靶标的行为）进行精致而准确的处理以及对持续动力学的明确解释（电离电子的行为）。开发了这三种互补工具后，我们将将它们应用于XFEL和强场激光脉冲中双电离的问题。特别是，我们将解决那些包含激光场和目标量子机械行为的强大影响的过程，因为这是当前方法基本上未经许可的制度。因此，我们将对NSDI和RESI进行研究，以及核心离子化，然后进行螺旋腐烂和由Xfel Light驱动的单个光子双电离。了解这些机制将为我们了解所有光介导的电子过程，包括重要的生物学作用，例如光合作用和眼睛的操作。 Attoscience的最终目标是控制这些过程并实现对社会的潜在利益。工具，例如该项目中开发的工具，可能被证明在此追求中是无与伦比的。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Core-resonance line-shape analysis of atoms undergoing strong-field ionization

强场电离原子的核心共振线形分析

DOI：
10.1088/1361-6455/ac9872
发表时间：
2022
期刊：
Atomic, Molecular and Optical Physics
影响因子：
0
作者：
Hartmann M
通讯作者：
Hartmann M

Attoscience in phase space

DOI：
10.1140/epjd/s10053-021-00199-0
发表时间：
2021-07-01
期刊：
EUROPEAN PHYSICAL JOURNAL D
影响因子：
1.8
作者：
Chomet, H.;Figueira de Morisson Faria, C.
通讯作者：
Figueira de Morisson Faria, C.

Polarization in strong-field ionization of excited helium

激发氦的强场电离极化

DOI：
10.1088/1361-6455/ac2e4a
发表时间：
2021
期刊：
Atomic, Molecular and Optical Physics
影响因子：
0
作者：
Bray A
通讯作者：
Bray A

Controlling quantum effects in enhanced strong-field ionisation with machine-learning techniques

DOI：
10.1088/1361-6455/aca4b0
发表时间：
2022-05
期刊：
Journal of Physics B: Atomic, Molecular and Optical Physics
影响因子：
0
作者：
H. Chomet;Samuel Plesnik;Constantin Nicolae;Jack Dunham;Lesley Gover;Timothy Weaving;Carla Figueira de Morisson Faria
通讯作者：
H. Chomet;Samuel Plesnik;Constantin Nicolae;Jack Dunham;Lesley Gover;Timothy Weaving;Carla Figueira de Morisson Faria

Resolving Quantum Interference Black Box through Attosecond Photoionization Spectroscopy

通过阿秒光电离光谱解决量子干涉黑匣子