Quantum controlled collisions; an empirical approach for studying the interaction potential of molecule-surface systems.

从星际介质中的星星形成到工业规模的化学品制造，分子与表面的相互作用在许多过程中起着关键作用。尽管它们很重要，但计算分子如何与表面相互作用是非常具有挑战性的，并且无法精确执行。相反，必须使用近似方法。虽然这些都在不断发展和进一步改进，毫无疑问，提供了重要的洞察许多表面现象，他们往往缺乏准确性和可靠性来解释和预测实验观察。现有的和新的实验技术，我们将采用的类型，需要进一步发展和改进的理论方法。在这个项目中，我们将开发和应用一个新的联合实验和理论的方法来研究分子和表面之间的相互作用，目的是能够提取有关这种相互作用的信息直接从我们的实验测量，而不是它必须被计算。这个提议的一个独特之处是，我们将使用磁分子干涉仪（MMI）来测量分子-表面碰撞。这种新建立的状态-状态散射技术已被证明能够量化与表面碰撞的基态氢分子的旋转波函数的幅度和相位的变化。干涉信号对分子量子态变化的敏感性将在该程序中用于重建分子与表面之间的相互作用势。该计划将包括从各种表面散射的氢分子的广泛MMI测量，包括离子表面，平坦金属表面和阶梯表面，代表不同类型的相互作用和不同水平的反应性。通过与莱顿的理论化学小组的合作，我们将开发一个从分析势能面计算MMI信号的程序。这将使我们能够比较计算和测量的信号，并确定最好地再现实验的函数形式和潜在参数。我们还将进一步开发我们独特的实验方法，以最大限度地提高其对相互作用势中细微差异的敏感性，从而能够区分准确再现其他最先进实验数据的不同理论模型。该项目的结果将为氢与各种固体表面的相互作用提供前所未有的见解，以及严格的实验基准，这将有助于开发新的精确的气体-表面相互作用理论模型。

The interaction of molecules with surfaces plays a pivotal role in many processes, from star formation in the interstellar medium to manufacturing chemicals on an industrial scale. Despite their importance, calculating how a molecule interacts with a surface is extremely challenging and cannot be performed exactly. Instead, approximate methods have to be used. Whilst these are constantly being developed and further improved, and unquestionably provide important insight into many surface phenomena, they often lack the accuracy and reliability to interpret and predict experimental observations. Existing and new experimental techniques, of the type we will employ, are needed to further develop and improve theoretical methods.In this project, we will develop and apply a new joint experimental-theoretical approach for studying the interaction between a molecule and a surface, with the aim of being able to extract information about this interaction directly from our experimental measurements rather than it having to be calculated. One unique aspect of this proposal is that we will use a magnetic molecular interferometer (MMI) for measuring molecule-surface collisions. This newly established state-to-state scattering technique has been shown to be capable of quantifying changes in the magnitude and phase of the rotational wavefunction of a ground state hydrogen molecule colliding with a surface. The sensitivity of the interference signal to changes in the quantum state of the molecule will be used in this program to reconstruct the interaction potential between the molecule and the surface. The program will include a wide range of MMI measurements of hydrogen molecules scattering from various surfaces, including ionic surfaces, flat metallic surfaces and stepped surfaces, representing different types of interactions and different levels of reactivity. Through a collaboration with the theoretical chemistry group in Leiden, we will develop a procedure for calculating MMI signals from analytical potential energy surfaces. This will allow us to compare calculated and measured signals and identify the functional forms and potential parameters which best reproduce the experiment. We will also further develop our unique experimental methodology to maximise its sensitivity to subtle differences in the interaction potential, to be able to distinguish between different theoretical models which accurately reproduce other state-of-the-art experimental data. The results of this project should provide unprecedented insight into the interaction of hydrogen with various solid surfaces as well as stringent experimental benchmarks which will help to develop new accurate theoretical models of gas-surface interactions.