Interfacial specificity of heterogeneous atmospheric and interstellar chemistry on ice/Spécificité interfaciale de la chimie atmosphérique et interstellaire sur la glace

冰上异质大气和星际化学的界面特异性/Spécificité interfaciale de la chimie atmosphérique et interstellaire sur la glace

• 批准号: 249915-2012
• 负责人: Ayotte, Patrick
• 金额: $ 2.55万
• 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: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507171
• 关键词: Interfacial; specificity; heterogeneous; atmospheric; interstellar

Our research program provides quantitative molecular-level descriptions of elementary heterogeneous processes on ice in order to improve our description of poorly understood atmospheric chemistry and astrophysical phenomena involving ice surfaces. Our approach relies on a combination of molecular beam and surface chemistry techniques, in concert with optical and electronic spectroscopy and microscopy, to study the complex coupled kinetics for adsorption, desorption and reaction of impurities onto thin ice films, as well as their absorption and diffusion within the bulk. Through molecular modelling and simulations, we provide detailed descriptions of how interfacial (photo)chemical processes differ from their bulk analogues using laboratory model systems inspired from atmospheric chemistry problems. The proposed work will improve our fundamental understanding of how simple acid molecules (HF, HCl, HBr, HNO3) adsorb onto ice, how they dissolve and become absorbed into ice, important elementary processes in atmospheric chemistry phenomena such as stratopheric ozone depletion. We also intend to consolidate recent and ongoing investigations of heterogeneous nitrates photochemistry in an attempt to better understand the source of the intense photochemical NOx fluxes observed to emanate from the snowpack to the polar boundary layer upon polar sunrise. Finally, recent developments in the separation of spin isotopomers of water poises us to undertake the development of an exciting new direction: studies of spin conversion chemistry of water in matrices and ice as well as its homogeneous and heterogeneous catalysis. This classical chemical physics problem promises to teach us how ortho-para ratios measured in the interstellar medium, such as those of water molecules sublimating from comets, are related to the temperature of the ice and also, of the primordial nebulae. It will also help establish experimental protocol for the preparation and storage of highly enriched samples of o-H2O and p-H2O for the study of how spin chemistry maps from reactants to products in chemical reactions involving indiscernible protons.

我们的研究计划提供了冰上基本异质过程的定量分子级描述，以改善我们对涉及冰面的大气化学和天体物理现象的描述。我们的方法依赖于分子束和表面化学技术的结合，并与光学光谱和显微镜一致，以研究复杂的耦合动力学，以吸附，杂质在薄冰膜上的吸附，解吸和反应，以及它们的吸收和扩散。通过分子建模和仿真，我们提供了使用大气化学问题启发的实验室模型系统，详细描述了界面（照片）化学过程与它们的批量类似物的不同。拟议的工作将提高我们对简单酸分子（HF，HCL，HBR，HNO3）如何吸附到冰上的基本理解，它们如何溶解并吸收到冰中，这是大气化学现象中的重要基本过程，例如地层臭氧消耗。 我们还打算巩固对异质硝酸盐光化学的最新和正在进行的研究，以便更好地了解观察到的强烈光化学NOX通量的来源，这些液体在极性日出时观察到从雪堆到边界层的散发出来。最后，在旋转同位素分离水的分离方面的最新发展使我们有助于我们开发一个令人兴奋的新方向：对矩阵和冰中水的自旋转化化学研究以及其同质和异质性催化。这个经典的化学物理问题有望教会我们如何在星际培养基中测得的Ortho-para比（例如从彗星脱落的水分子的比率）与冰的温度以及原始的星云有关。它还将有助于建立实验方案，以制备和存储高度富集的O-H2O和P-H2O样品，以研究如何在涉及不可见力蛋白质的化学反应中从反应物到产物的自旋化学图。