期刊
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
卷 226, 期 3, 页码 397-403出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/S1387-3806(03)00085-X
关键词
electron molecule scattering; negative ions in molecules of biological interest
We have compared the negative ion production processes in thymine (T) and 5-bromouracil (BrU) after impact of low energy electrons (0-2 eV). In agreement with earlier studies we have observed in BrU a long lived parent ion BrU- and fragment ions Br- and Uyl(-) with cross sections in the 10(-14) cm(2) range. In contrast with other observations in thymine, the most intense ions are found to be (T-H)(-) fragment ions and not the parent ion T-. For the fragment ions Br-/BrU, Uyl(-)/BrU and (T-H)(-)/T the shape of the cross section vs. electron energy reveals a complex nature. Close to zero energy, several peaks separated by a few hundreds of meV appear in these cross sections, instead of only one peak reported in earlier works. Our observations are understood as vibrational structures due to predissociation of rather long lived anion states, possibly dipole bound states, by valence Pi* resonant states, close to zero energy. (C) 2003 Elsevier Science B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据