Physicochemical Investigations of Aerosol Particles

气溶胶是悬浮在气体中的小颗粒，它们在我们的大气中的存在在许多方面影响着地球的环境。例如，它们对辐射强迫的直接影响影响气候变化，它们是许多不同化学反应的场所，它们充当云凝结核。此外，气雾剂每天都会影响人类健康，因为它们当然存在于我们呼吸的空气中。因此，了解气溶胶的性质对于量化其对气候和健康的影响至关重要。目前，我们对气溶胶的化学和物理知识都存在许多空白。拟议研究方案的重点是通过同时开发与大气相关的气溶胶颗粒研究的实验和理论工具来解决其中许多知识差距。对单个颗粒的光学捕获将是研究气溶胶的主要技术。通过在单粒子水平上进行测量，有可能在广泛的时间范围内以高精度和低不确定性研究微物理和化学过程。一项全面的研究计划将基于四个相互关联的项目来实施，每个项目都围绕以下四个光学陷阱之一进行设计：1.气溶胶光学镊子，2.光学贝塞尔光束陷阱，3.全息光学镊子，和4.低温光学镊子。这些光学陷阱将被用来研究影响云凝结核和云形成过程的几个基本气溶胶过程。对气溶胶科学至关重要的参数，如吸湿性、表面张力、粘度、电磁辐射的散射和吸收以及热量和传质，将以非常高的精度确定。更深入、更详细地了解这些现象是拟议研究项目的一个主要目标，因为这将极大地提高我们对气溶胶及其在气候中的作用的认识。光学陷阱将能够检查尺寸从几微米到纳米尺寸的颗粒，并将处于气溶胶科学领域研究的前沿。总而言之，拟议的计划旨在为气溶胶研究开发最先进的分析工具，同时验证或改进我们目前用来理解大气气溶胶化学和物理的模型。

Aerosols are small particles suspended in a gas and their presence in our atmosphere affects Earth's environment in many ways. For example, their direct effect on radiative forcing influences climate change, they serve as sites for many different chemical reactions, and they act as cloud condensation nuclei. Furthermore, aerosols impact human health on a daily basis as they are, of course, present in the air we breathe. Understanding the properties of aerosols is therefore of crucial importance for quantifying their impact on climate and health. Currently, there exist many gaps in both our chemical and physical knowledge of aerosols. The focus of the proposed research program is to address many of these knowledge gaps through the simultaneous development of experimental and theoretical tools for the study of atmospherically relevant aerosol particles. Optical trapping of individual particles will be the primary technique used to study aerosols. By taking measurements at the single particle level, it is possible for microphysical and chemical processes to be investigated with great accuracy and low uncertainties over a wide range of timescales. A comprehensive research program will be implemented based on four inter-related projects, each of which is designed around one of the following four optical traps: 1. Aerosol optical tweezers, 2. Optical Bessel beam trap, 3. Holographic optical tweezers, and 4. Low temperature optical tweezers. These optical traps will be used to study several fundamental aerosol processes that influence cloud condensation nuclei and the process of cloud formation. Parameters vital to aerosol science such as hygroscopicity, surface tension, viscosity, scattering and absorption of electromagnetic radiation, and heat and mass transfer will be determined with very high precision. Achieving a deeper, more detailed understanding of these phenomena is a major goal of the proposed research project, as it will greatly improve our knowledge of aerosols and their role in climate. The optical traps will be able to examine particles with sizes ranging from several micrometers down into the nanometer size regime and will be at the forefront of research in the field of aerosol science. In broad terms, the proposed program aims to develop state-of-the-art analytical tools for aerosol research and, simultaneously, validate or improve the models we currently use to understand the chemistry and physics of atmospheric aerosols.**