Laser Spectroscopy of Ion and Clusters

在这个由化学系实验物理化学计划资助的项目中，加州大学伯克利分校的Saykally教授将继续他对水和水团簇性质的实验和理论研究计划。利用太赫兹和红外腔衰荡光谱对水团簇的平移振动-旋转-隧道(VRT)带进行了详细的研究。新的数据将包括平移和振动VRT带，将用于生成改进的水二聚体势能面。反过来，这些将被用来构建更大的水团簇和液态水的势，这将通过量子蒙特卡罗和分子动力学方法的实验进行测试。类似的方法将用于质子化水团簇的研究，使用太赫兹速度调制光谱和超音速放电等离子体。这里的目的是阐明质子转移动力学的细节，例如质子隧穿速率与分子间距离和取向的关系。水是地球上最基本的物质，加强我们对其性质的理解将影响许多科学和技术领域。最近在地球大气中发现了水团，预计将对其化学成分产生重要影响。研究生和本科生以及博士后研究助理将参与这项研究。因此，他们将在当代物理化学的前沿领域获得宝贵的经验。Saykally教授将继续通过概述讲座、大众媒体和其他媒体，在机会出现时积极参与推广计划，将科学的新发展带给广大公众。

In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Professor Saykally of the University of California at Berkeley will continue his experimental and theoretical research program on the properties of water and water clusters. Detailed studies of the translational and librational vibration-rotation-tunneling (VRT) bands of water clusters will be undertaken by means of terahertz and infrared cavity ring-down spectroscopies. The new data, which will include translational and librational VRT bands, will be used to generate improved water dimer potential surfaces. These, in turn, will be used to construct potentials for larger water clusters and liquid water, which will be tested against experiment with Quantum Monte Carlo and molecular dynamics methods. A similar approach will be used for the study of protonated water clusters, using terahertz velocity modulation spectroscopy and supersonic discharge plasmas. The goal here is to elucidate details of the proton transfer dynamics, such as the dependence of proton tunneling rates on intermolecular distances and orientation.Water is the most fundamental substance on our planet, and enhancing our understanding of its nature will impact many areas of science and technology. Water clusters have recently been detected in the earth's atmosphere, and are predicted to have important effects on its chemistry.Graduate and undergraduate students as well as postdoctoral research associates will participate in this research. They will thereby gain valuable experience in a forefront area of contemporary physical chemistry. Professor Saykally will continue to be active in an outreach program through overview lectures, the popular press, and other media, as opportunities arise, to bring new developments in science to the public at large.