Denifl Stephan, Zappa Fabio, Mähr Ingo, Mauracher Andreas, Probst Michael, Märk Tilmann D, Scheier Paul
Institut für Ionenphysik and Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
J Am Chem Soc. 2008 Apr 16;130(15):5065-71. doi: 10.1021/ja075972m. Epub 2008 Mar 13.
The inelastic electron interaction (ionization/attachment) with chloroform embedded in helium droplets has been studied utilizing a two-sector field mass spectrometer. Positive mass spectra have been recorded at the electron energy of 70 eV and are compared with previous results in the gas phase and with other systems embedded in helium droplets. Moreover, the negative ion mass spectrum has been recorded at the electron energy of 1.5 eV. Both negative and positive mass spectra show that chloroform clusters are easily formed by embedding single molecules in the helium droplets. Moreover, for anions appearing in the mass spectrum, the ion yield has been determined as function of the electron energy. While no parent anion of chloroform can be observed in the gas phase, the present cluster environment allows the stabilization of the transient negative ion. The influence of the helium droplet upon the ionization or attachment process of the embedded chloroform is discussed.
利用双扇形场质谱仪研究了嵌入氦滴中的氯仿的非弹性电子相互作用（电离/附着）。在70 eV的电子能量下记录了正质谱，并与气相中的先前结果以及嵌入氦滴中的其他系统进行了比较。此外，在1.5 eV的电子能量下记录了负离子质谱。正负质谱均表明，通过将单个分子嵌入氦滴中很容易形成氯仿团簇。此外，对于质谱中出现的阴离子，已确定离子产率与电子能量的函数关系。虽然在气相中无法观察到氯仿的母体阴离子，但当前的团簇环境允许瞬态负离子稳定。讨论了氦滴对嵌入氯仿的电离或附着过程的影响。
