R-matrix suites for multielectron attosecond dynamics in atoms and molecules irradiated by arbitrarily polarised light

在这个项目中，我们将开发新的软件，用于在任意偏振的强超短光场中精确描述原子和分子系统。这涉及到推广两个世界领先的代码套件：用于超快原子动力学的r矩阵与时间相关代码（RMT）和用于分子中电子/正电子散射和光电离过程的UKRmol+套件。通过将这些代码以易于使用和有效运行的形式提供给更广泛的社区，我们将帮助在英国建立软件基础设施。在过去的几十年里，激光技术的重大发展导致了阿秒科学的诞生：激光现在可以产生极短的脉冲（大约0.1飞秒或持续时间10（-16）秒）来成像和控制原子和分子中电子的运动。例如，这一发展使科学家们能够“看到”电荷在分子电离后是如何在分子中转移的，这是一个具有生物学重要性的过程（例如在光合作用中）。光可以当作电磁波来对待；电场振荡的方向决定了光的偏振。这种偏振反过来又决定了光如何与物质相互作用。直到最近，强烈的超短光脉冲都是线性极化的。然而，最近有可能产生具有不同类型偏振的激光脉冲。这些最新的技术发展带来了新的科学研究领域和新的机会。通过控制光脉冲的偏振，人们可以控制电子动力学，甚至对其进行微调：简单地说，使用在一维以上振荡的光脉冲在实验中提供了额外的控制参数，这就是所谓的多维光谱的潜在机制。随着实验开始探索量子世界和经典世界的界面，这个领域正变得越来越有趣。此外，具有椭圆偏振的光脉冲将使手性分子中的电子动力学的详细研究成为可能。（手性分子是指那些不能与镜像重叠的分子，比如人的手）。这些分子非常有趣：许多生物学上重要的分子，比如构成生物体的氨基酸和糖，都是“同手性的”：生命中只有一种变体（但绝不是镜像）。我们需要新的计算机代码，能够在任意偏振光下处理一般的原子和分子系统，以补充实验进展，协助理论解释并指导它们。目前，RMT代码可以模拟线性偏振光场中的原子。扩展它们来处理任意偏振光的影响是一项艰巨的任务：它需要解除对称性限制，这限制了以前计算的大小，因此，要考虑到更大规模的计算，编码效率的显著提高是必要的。此外，我们将通过开发一种等效的方法来以时间依赖的方式处理分子，从而大规模扩大该方法的影响。研究激光脉冲对分子的影响所需的数据将由UKRmol+套件生成。这反过来又要求对这些代码进行彻底检查，以便它们能够以有效的方式产生足够准确的输入。该项目中的计算开发将与CCPQ社区紧密相连，该社区涉及英国各地的研究小组，开发用于原子和分子物理以及计算化学的科学软件。通过CCPQ，我们不仅可以分享代码套件，还可以分享所获得的专业知识和软件开发技能。

In this project, we will develop new software for the accurate description of atoms and molecular systems in intense, ultra-short light fields with arbitrary polarisation. This involves generalising two world-leading suites of codes: The R-matrix with time-dependence codes (RMT) for ultra-fast atomic dynamics and the UKRmol+ suite for electron/positron scattering and photoionisation processes in molecules. By making these codes available to the wider community, in a form that can be easily used and efficiently run, we will help build the software infrastructure in the UK. Significant development in laser technology over the last couple of decades has led to the birth of attosecond science: lasers are now available that can produce extremely short pulses (around 0.1 femtosecond or 10(-16) s in duration) to image and control the motion of electrons in atoms and molecules. This development has, for example, enabled scientists to 'see' how charge is transferred in a molecule after it is ionised, a process that has biological importance (for example, in photosynthesis).Light can be treated as an electromagnetic wave; the direction in which the electric field oscillates defines the polarisation of the light. This polarisation, in turn, determines how the light interacts with matter. Until very recently intense, ultra-short light pulses were linearly polarised. However, it has recently become possible to generate laser pulses with different types of polarisation. New scientific research areas and new opportunities have become available via these latest technological developments. With control over the polarisation of light pulses, one can control the electron dynamics and even fine-tune it: In simple terms, using light pulses which oscillate in more than one-dimension gives an additional control parameter in experiments, and this is the underlying mechanism in so-called multidimensional spectroscopy. This field is becoming increasingly interesting, as experiments begin to probe the interface of the quantum and classical worlds. In addition, light pulses with elliptical polarisation will enable the detailed study of electron dynamics in chiral molecules. (Chiral molecules are those that cannot be superimposed to their mirror images, like human hands). These molecules are immensely interesting: a lot of biologically important molecules, like the amino acids and sugars that are building blocks of living organisms are 'homochiral': only one variant is present in life (but never its mirror image). New computer codes, which can handle general atomic and molecular systems in arbitrarily polarised light are needed to complement experimental advances, to assist in their theoretical interpretation and also to guide them. At present, the RMT codes can model atoms in a linearly polarised light field. Expanding them to treat the effect of arbitrarily polarised light is a substantial task: It requires lifting symmetry restrictions which have limited the size of previous calculations, and consequently a significant improvement in the codes' efficiency to account for the much larger-scale calculations will be necessary. In addition, we will massively expand the impact of the method by developing an equivalent method to treat molecules in a time-dependent fashion. The data needed to study the effect of the laser pulses on molecules will be generated by the UKRmol+ suite. This, in turn, requires the overhauling of these codes so they can produce sufficiently accurate input in an efficient way. The computational development within this project will be strongly connected to the CCPQ community, which involves research groups across the UK developing scientific software for use in atomic and molecular physics and computational chemistry. Through CCPQ we will not only share the suites of codes, but also the expertise and software development skills gained.