大气环境中的水分子团簇分布和H^+(H_2O)_n(n=4～16)离子的解离  

Water Cluster Distribution under Ambient Conditions and Dissociation of H^+(H_2O)_n(n=4～16) Using Mass Spectrometry in Atmosphere

作　　者：杨鹏[1] 叶招莲[2] 蒋公羽[1] 李周[1] 丁传凡[1] 侯惠奇[2] 

机构地区：[1]复旦大学化学系,上海200433 [2]复旦大学环境科学研究所,上海200433

出　　处：《化学学报》2009年第17期2031-2037,共7页Acta Chimica Sinica

基　　金：国家科技支撑计划(No.2006BAK03A21)资助项目

摘　　要：报道了用质谱学方法首次测得的大气中各种水的团簇分布情况.表明在室内大气环境下,水主要是以几个至几十个水分子所组成的分子团簇的形式存在,且团簇的分布与空气湿度,即水在空气中的分压有关.实验中,除观测到空气中也存在前人已报道过的具有笼状结构的H+(H2O)21外,还观测到其他几种较稳定结构的水的团簇,即H+(H2O)4,H+(H2O)10和H+(H2O)15.实验中所测得的水分子团簇分布结果与使用的离子源以及质量分析器种类无关.我们还用碰撞诱导解离(CID)的方法研究了H+(H2O)n(n=4～16)离子的碰撞解离产物,结果表明,对于H+(H2O)n(n=4～16)的离子,其较稳定的离子的碰撞解离产物均为H+(H2O)n(n=4～6).我们还进一步研究了H+(H2O)10离子的碰撞解离产物与碰撞气体(即Ar气)密度的关系,得到了碰撞气体密度与碰撞解离产物分布的关系.The distribution of water clusters under ambient conditions was first tested using a triple-quadrupole mass spectrometer coupled with a dielectric barrier discharge ionization source. The water exists as clusters rather than a single molecule under the ambient conditions, and the cluster distribution is dependent on the humility of atmosphere, or the water vapor pressure. In addition to the cluster with the magic number n=21, H^＋（H2O）n was also observed in the ambient condition, and H^＋（H2O）4, H^＋（H2O）10 and H^＋（H2O）15 were found more stable according to the experiment. The dissociation products of H^＋（H2O）n （n=4-16） clusters were further studied with a collision induced dissociation （CID） method. The product ions were mainly H^＋（H2O）n （n=4-6）. The CID products of H^＋（H2O）10 with the collision gas pressure were also studied.

关 键 词：大气环境 水分子团簇 质谱 碰撞解离产物 

分 类 号：O641.1[理学—物理化学]