Huber D, Beikircher M, Denifl S, Zappa F, Matejcik S, Bacher A, Grill V, Märk T D, Scheier P
Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences, Leopold Franzens Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
J Chem Phys. 2006 Aug 28;125(8):084304. doi: 10.1063/1.2336775.
The dissociative electron attachment to the gas phase nucleobase adenine is studied using two different experiments. A double focusing sector field mass spectrometer is utilized for measurements requiring high mass resolution, high sensitivity, and relative ion yields for all the fragment anions and a hemispherical electron monochromator instrument for high electron energy resolution. The negative ion mass spectra are discussed at two different electron energies of 2 and 6 eV. In contrast to previous gas phase studies a number of new negative ions are discovered in the mass spectra. The ion efficiency curves for the negative ions of adenine are measured for the electron energy range from about 0 to 15 eV with an electron energy resolution of about 100 meV. The total anion yield derived via the summation of all measured fragment anions is compared with the total cross section for negative ion formation measured recently without mass spectrometry. For adenine the shape of the two cross section curves agrees well, taking into account the different electron energy resolutions; however, for thymine some peculiar differences are observed.
使用两种不同的实验研究了气相核碱基腺嘌呤的离解电子附着。双聚焦扇形场质谱仪用于需要高质量分辨率、高灵敏度以及所有碎片阴离子相对离子产率的测量，而半球形电子单色仪用于高电子能量分辨率的测量。在2 eV和6 eV这两种不同的电子能量下讨论了负离子质谱。与之前的气相研究不同，在质谱中发现了许多新的负离子。在电子能量范围约为0至15 eV、电子能量分辨率约为100 meV的条件下测量了腺嘌呤负离子的离子效率曲线。将通过对所有测量的碎片阴离子求和得到的总阴离子产率与最近在没有质谱分析的情况下测量的负离子形成总截面进行了比较。对于腺嘌呤，考虑到不同的电子能量分辨率，两条截面曲线的形状吻合得很好；然而，对于胸腺嘧啶，观察到了一些特殊的差异。
