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，用于精确描述具有任意偏振的强、超短光场中的原子和分子系统。这包括概括两套世界领先的代码：具有时间依赖代码(RMT)的R-矩阵，用于超快原子动力学，以及用于电子/正电子散射和分子中的光电离过程的UKRmol+套件。通过将这些代码以易于使用和高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。激光技术在过去几十年中的重大发展导致了阿秒科学的诞生：现在可以使用激光产生极短的脉冲(持续时间约为0.1飞秒或10(-16)S)来成像和控制电子在原子和分子中的运动。例如，这一进展使科学家能够看到分子在电离后电荷是如何转移的，这一过程具有生物学意义(例如，在光合作用中)。光可以被视为电磁波；电场振荡的方向决定了光的偏振。这种偏振反过来决定了光与物质的相互作用方式。直到最近，强烈的超短光脉冲都是线性偏振的。然而，最近已经有可能产生具有不同类型偏振的激光脉冲。通过这些最新的技术发展，新的科学研究领域和新的机会已经成为可能。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一个额外的控制参数，这就是所谓的多维光谱学的基本机制。随着实验开始探索量子世界和经典世界的界面，这个领域变得越来越有趣。此外，椭圆偏振光脉冲将使详细研究手性分子中的电子动力学成为可能。(手性分子是那些不能叠加到镜像上的分子，就像人类的手一样)。这些分子非常有趣：许多具有生物学意义的分子，比如构成生命有机体的氨基酸和糖，都是同质的：生命中只存在一个变体(但永远不是它的镜像)。需要新的计算机代码，它可以处理任意偏振光中的一般原子和分子系统，以补充实验进展，帮助它们的理论解释，并指导它们。目前，RMT代码可以对线偏振光场中的原子进行建模。扩展它们以处理任意偏振光的影响是一项实质性的任务：它需要取消对称限制，这些限制限制了以前的计算的大小，因此需要显著提高代码的效率，以应对规模大得多的计算。此外，我们将通过开发一种等效的方法来处理依赖于时间的分子，从而大规模扩展该方法的影响。研究激光脉冲对分子影响所需的数据将由UKRmol+套件产生。反过来，这又需要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，我们不仅将分享代码套件，还将分享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.