Investigation of the condensation and freezing behavior of freely suspended supercooled molecular gases and particles in the nano to millimeter size range

研究纳米至毫米尺寸范围内悬浮的过冷分子气体和颗粒的冷凝和冻结行为

• 批准号: 189900837
• 负责人: Professor Dr. Sigurd Bauerecker
• 金额: --
• 依托单位: Institut für Physikalische und Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/189900837?language=en
• 关键词: Investigation; condensation; freezing; behavior; freely

In the project supercooled molecules as well as nano, micro and millimeter droplets shall be investigated with respect to their condensation, aggregation and freezing behavior in a gaseous vicinity. For this purpose, optical methods as high resolution infrared spectroscopy, Raman spectroscopy, terahertz spectroscopy (by use of synchrotron sources), and high-speed filming will be applied. Theoretical support will especially be delivered by collaborators through computer simulations. From our group finite element methods for the investigation of heat production and distribution during freezing as well as the discrete dipole approximation method for optical particle characterization will be used. One main focus will be a new, improved collisional cooling system which shall be developed for cooling, supercooling and spectroscopy of molecular gases, nano and micro aerosols in the temperature region of 4 to 400 K. For this system our experiences of the last 15 years with the old well-tried system will be considered as well as other technical improvements. As a key technology a more powerful sample-gas inlet system for supercooling of gases shall be constructed. Performing high resolution spectroscopy of supercooled gases we aim at an improved understanding of the intra-molecular dynamics via global potential hyper-surfaces. Highly qualitative measuring data shall be delivered for data bases as HITRAN or GEISHA under consideration of applications, e.g., in environmental sciences. Concerning aerosols, water and other substances stand in the focus as they are important for the physical chemistry of the atmospheres of the Earth and other planets and their satellites and also for interstellar gases. Especially the freezing behavior of microdroplets within an aerosol cloud shall be unraveled (concerning dynamics, size-, shape-, phase-, and structure-evolution, heat production and transport, optical constants); last but not least for the interpretation of Raman lidar data. Concerning freely suspended droplets from water and aqueous solutions in the millimeter size range, the first rapid freezing stage which passes in milliseconds shall be investigated and characterized as well as the evolving dendritic network ice. During the first project stage we observed an electric effect showing freezing potentials of up to 6 V. This effect shall be unraveled now. The influence of the asymmetric network structure of the dendritic ice on the ion distribution within the final ice shall be explained, especially the impact on the particle chemistry and electric potential generation in thunderclouds. Furthermore, we will study the analogy of the formation of regular dendritic ice to the formation of snowflakes in air, as well as the transition towards smaller particles in the micrometer size range.

在该项目中，应研究过冷分子以及纳米、微米和毫米液滴在气态附近的冷凝、聚集和冻结行为。为此，将应用光学方法，如高分辨率红外光谱、拉曼光谱、太赫兹光谱（通过使用同步加速器源）和高速成膜。合作者将通过计算机模拟提供理论支持。从我们的小组有限元方法的热生产和分布的调查，在冻结以及离散偶极子近似方法的光学粒子表征将被使用。一个主要的焦点将是一个新的，改进的碰撞冷却系统，该系统将被开发用于4至400 K温度范围内的分子气体，纳米和微米气溶胶的冷却，过冷和光谱学。对于这一系统，我们将考虑过去15年来在旧的行之有效的系统方面的经验以及其他技术改进。作为一项关键技术，应建造一个更强大的样气进气系统，以实现气体的过冷。执行高分辨率光谱的过冷气体，我们的目标是通过全球潜在的超曲面分子内动力学的更好的理解。应向考虑应用的数据库（如HITRAN或GEISHA）提供高质量的测量数据，例如，在环境科学中。关于气溶胶，水和其他物质是重点，因为它们对地球和其他行星及其卫星大气层的物理化学以及星际气体都很重要。特别是在气溶胶云内的微滴的冻结行为将被解开（涉及动力学，大小，形状，相位和结构演变，热产生和传输，光学常数）;最后但并非最不重要的是解释拉曼激光雷达数据。关于毫米级水和水溶液中自由悬浮的液滴，应研究和表征毫秒级的第一快速冻结阶段以及不断发展的树枝状网络冰。在第一个项目阶段，我们观察到一个电效应，显示冻结电位高达6 V。应解释树枝状冰的非对称网络结构对最终冰内离子分布的影响，特别是对雷暴云中粒子化学和电势产生的影响。此外，我们还将研究规则树枝状冰的形成与空气中雪花形成的类比，以及向微米尺寸范围内较小颗粒的过渡。

项目成果

Study of the high resolution spectrum of (SOO)-S-32-O-16-O-18: The nu(1) and nu(3) bands

(SOO)-S-32-O-16-O-18 的高分辨率光谱研究：nu(1) 和 nu(3) 波段

• DOI: 10.1016/j.jqsrt.2015.08.010
• 发表时间: 2016
• 期刊: Journal of Quantitative Spectroscopy & Radiative Transfer
• 影响因子: 2.3
• 作者: O.N. Ulenikov;E.S. Bekhtereva;Yu.V. Krivchikova;V.A. Zamotaeva;T. Buttersack;C. Sydow;S. Bauerecker
• 通讯作者: S. Bauerecker