ICE Chemistry And Physics: Astrophysics, Dynamics and Environment (ICECAPADE)

ICE 化学和物理：天体物理学、动力学和环境 (ICECAPADE)

• 批准号: RGPIN-2017-05395
• 负责人: Ayotte, Patrick
• 金额: $ 2.04万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=644356
• 关键词: ICE; Chemistry; Physics; Astrophysics; Dynamics

Innovative applications of molecular beam methods will be deployed to study elementary heterogeneous (photo)chemical processes on ice surfaces which are of interest to develop molecular-level interpretations for astrophysical phenomena in the interstellar medium, for fundamental interfacial chemical dynamics and for atmospheric chemistry processes relevant to the polar boundary layer.*******We propose to use a novel methodology based on a recently developed magnetically focused molecular beam source, enabling the production of water vapor highly enriched in the ortho-H2O nuclear spin isomers, to devise and optimize separation strategies and the transfer of ortho-H2O, and of the resulting spin polarisation, to the condensed phase and surfaces. Confinement effects are germane to any storage methodologies therefore, we propose to perform systematic studies of nuclear spin conversion that will shed light on intra- and inter-molecular contributions to the underlying mechanism. This may contribute to improve storage strategies thereby extending the lifetime of condensed phase water samples enriched in ortho-H2O. These methodological developments will set the stage for fundamental interfacial chemical dynamics, heterogeneous catalysis of nuclear spin conversion and important NMR spectroscopy applications as well as for laboratory studies of the behavior of the nuclear spin isomers of water observed in comae and protoplanetary disks.*******Photochemical processes are often enhanced in molecules adsorbed onto ice surfaces due to their peculiar solvation environment. We will use thin amorphous solid water films as surrogates for the quasi-liquid layer that resides at the ice surface in the natural environment and study the surface specificity of elementary processes responsible for intense NOx photochemical fluxes that emanate from the sunlit snowpack to the boundary layer upon polar Spring. Using our molecular beam/surface spectroscopy and kinetics methodology, as well as ultrafast spectroscopic techniques, we will investigate heterogeneous NO2 hydrolysis and photolysis in/on condensed water and provide improved mechanistic descriptions and quantitative kinetic parameters. This will advance kinetic modelling efforts of the complex coupled kinetics involved in this important natural phenomenon.*******Finally, environmental cryogenic electron microscopy studies of the heterogeneous nucleation and growth of ice will reveal the role played by substrate properties and growth conditions on the structure and morphology of thin vapor-deposited ice films which contribute to the interpretation of our spectroscopic/kinetics work. They will be pursued in concert within our FQR-NT funded project, sponsored by industrial partner Rio Tinto-Alcan International Limited, on the mitigation of mineral dust emissions at the Site de Disposition des Résidus de Bauxite, Jonquière, Qc.*****

将利用分子束方法的创新应用，研究冰表面上的基本非均质（光）化学过程，这些过程对于在分子一级解释星际介质中的天体物理现象、基本界面化学动力学和与极地边界层有关的大气化学过程很有意义。我们建议使用一种新的方法的基础上，最近开发的磁聚焦分子束源，使生产的水蒸气高度富集的邻-H2O核自旋异构体，设计和优化分离策略和转移的邻-H2O，和由此产生的自旋极化，凝聚相和表面。约束效应是密切相关的任何存储方法，因此，我们建议进行系统的研究，核自旋转换，将揭示内部和分子间的贡献的基本机制。 这可能有助于改善存储策略，从而延长浓缩相水样品的寿命富含邻-H2O。 这些方法学的发展将为基本界面化学动力学、核自旋转换的多相催化和重要的核磁共振光谱应用以及对后发座和原行星盘中观察到的水的核自旋异构体行为的实验室研究奠定基础。*由于冰表面特殊的溶剂化环境，吸附在冰表面上的分子的光化学过程常常被增强。 我们将使用薄的无定形固体水膜作为准液体层，居住在自然环境中的冰表面的替代品，并研究负责强烈的氮氧化物光化学通量的基本过程的表面特异性，从阳光照射的积雪发出的边界层极地春季。 使用我们的分子束/表面光谱和动力学方法，以及超快光谱技术，我们将研究非均相NO2水解和光解/冷凝水，并提供改进的机制描述和定量动力学参数。 这将推进这一重要自然现象中涉及的复杂耦合动力学的动力学建模工作。最后，环境低温电子显微镜研究冰的非均质成核和生长将揭示所发挥的作用的基板性能和生长条件上的结构和形态的薄气相沉积的冰膜，这有助于我们的光谱/动力学工作的解释。这些项目将在我们的BERR-NT资助项目中协调进行，该项目由工业合作伙伴力拓-加拿大铝业国际有限公司赞助，旨在减少昆士兰州琼基耶尔Résidus de BERR-NT处置现场的矿物粉尘排放。*