醇/水混合团簇的多光子电离质谱及从头算研究

利用多光子电离技术和飞行时间质谱仪实验研究了醇/水混合团簇的光电离质谱。在脉冲激光波长为355nm条件下，观测到以质子化(ROH)n(H2O)H+ 混合团簇离子和(ROH)nH+团簇离子为主的电离产物。醇水混合团簇电离后团簇离子发生内部质子化转移反应是形成质子化团簇离子的主要原因。应用量化计算，构造了质量数较小的几个团簇离子的可能的空间几何构型，发现二元团簇离子(CH3OH)n(H2O)H+是以(CH3OH)H+作为内核离子，再通过氢键与其它分子组合而构成团簇离子。

Multiphoton ionization mass spectrum of alcohol-water complex cluster and ab initio calculation

Alcohol-water complex clusters were studied by using multiphoton ionization technique and time-of-flight mass spectrometer. Laser with 355nm wavelengths were used as ionized source, protonated cluster ions (ROH)n(H2O)H+ and (ROH)nH+ were observed where the R=CH3 or C2H5. The formation of (ROH)n(H2O)H+ is mainly through proton transfer reaction intra alcohol-water clusters ions after laser multiphoton ionization. Some possible geometric structures of (CH3OH)n(H2O)H+ with relatively small sizes were guessed using ab initio calculation method. The structures show that the (CH3OH)H+ trends as the ion’s center, and then it combines with other methanol or ethanol molecule to form the final stable complex cluster ions.