Potential Energy Surfaces for the Chemistry of Cold Matter

原子和分子冷却到非常接近绝对零度的温度时，它们的行为发生了令人惊讶的变化，因为它们受到量子力学的奇怪效应的支配。这从根本上改变了分子相互作用的方式，改变了化学反应，并有可能使它们通过激光和磁场精确控制。除了这种受控的化学物质，分子在这些温度下的可能应用还包括量子技术，如用于下一代GPS的便携式原子钟和量子计算机，这些计算机可以解决令当前超级计算机困惑的问题。在开发这些有希望的进展之前，我们首先需要学习如何将各种分子冷却到所需的温度，进一步了解原子和分子在这些极端条件下的行为，并开发更精确的控制它们的方法。这通常是通过设计和进行精细的实验来实现的，但理论量子化学计算的输入对于正确解释结果至关重要。该项目的目的是开发新的理论工具，以提高计算这些冷系统的能量如何随着原子/分子的相对位置的调整而变化，以及不同元素在这些条件下可能如何表现的准确性和效率。这将需要为重、碱和碱土金属开发新的基组，并将其与仔细考虑离散量子力学效应相结合，以开发一种易于应用于各种冷物质系统的计算协议。开发的技术的第一个应用是研究如何在超低温下通过一种被称为共鸣冷却的过程产生氟化钙，一种能够产生强烈远程相互作用的分子。这项工作中开发的方法将使所有人都可以使用，但在冷物质领域工作的理论家和实验者都会特别感兴趣。将以这样一种方式传达结果，即有关各方将能够很容易地将这些方法纳入其现有工作流程，从而加快对结果的分析，并允许作出更好的预测和解释。最终，这项工作的结果将指导实验朝着正确的方向发展，提高取得进展的速度，并防止在不太可能产生有用结果的系统上进行昂贵的实验。

The cooling of atoms and molecules to temperatures very close to absolute zero produces a surprising change in their behaviour as they become dominated by the bizarre effects of quantum mechanics. This fundamentally changes how molecules interact with each other, altering chemical reactions and potentially making them precisely controllable via lasers and magnetic fields. In addition to this controlled chemistry, possible applications of molecules at these temperatures include quantum technologies such as portable atomic clocks for use in next-generation GPS and quantum computers that can solve problems way beyond those that confound current supercomputers.Before these promising advances can be developed, we first need to learn how to cool a wide variety of molecules to the required temperatures, generate further knowledge about how atoms and molecules behave in these extreme conditions, and develop more precise ways of controlling them. This is typically approached by designing and carrying out experiments in exquisite detail, but the input of theoretical quantum chemistry calculations is vital to correctly interpret the results. The aim of this project is to develop new theoretical tools that will increase both the accuracy and efficiency of computing how the energy of these cold systems varies as the relative positions of the atoms/molecules are adjusted, and how the different elements may behave under these conditions. This will require the development of new basis sets for the heavy alkali and alkaline earth metals and combining this with a careful consideration of discrete quantum mechanical effects to develop a computational protocol that can be readily applied to a wide variety of cold matter systems. The first application of the techniques developed is proposed to be an investigation of how calcium fluoride, a molecule that is capable of strong long-range interactions, might be produced at ultracold temperatures through a process known as sympathetic cooling.The methods developed in this work will be made available and accessible to all, but will be of particular interest to both theoreticians and experimentalists working in the cold matter field. The results will be communicated in such a way that interested parties will easily be able to incorporate the methods into their existing work-flow, accelerating the analysis of results and allowing for better predictions and interpretations to be made. Ultimately the results of this work will guide experiment in the right direction, increasing the speed at which progress is made and preventing expensive experiments being carried out on systems that are unlikely to yield useful results.