The Open University, Department of Physical Sciences, Walton Hall, Milton Keynes, MK7 6AA, UK.
Phys Chem Chem Phys. 2013 Jan 21;15(3):998-1005. doi: 10.1039/c2cp42966g.
A detailed experimental investigation of the dissociative electron attachment (DEA) process to acetaldehyde, CH(3)CHO is presented. To investigate this process we use a time of flight spectrometer coupled with the velocity slice imaging technique. DEA in CH(3)CHO is found to lead to the formation of CH(3)(-), O(-), OH(-), C(2)H(-), C(2)HO(-) and CH(3)CO(-) anionic products produced through scattering resonances in the electron energy range of 6 to 13 eV. Of these product ions only O(-) is formed with any measurable kinetic energy distribution indicating a two-body dissociation process. CH(3)CO(-), although formed with very low kinetic energy, shows anisotropy in the velocity slice image, indicating ejection of the H atom in the 180° direction with respect to the electron beam. The low kinetic energy distributions and absence of any anisotropy in the angular distributions of the other product ions indicate that they are formed through multiple fragmentation of the transient molecular negative ion. The angular distribution of O(-) is analysed in terms of the various partial waves.
本文对乙醛（CH(3)CHO）的离解电子俘获（DEA）过程进行了详细的实验研究。为了研究这一过程，我们使用飞行时间谱仪结合速度切片成像技术。研究发现，CH(3)CHO 中的 DEA 导致 CH(3)(-)、O(-)、OH(-)、C(2)H(-)、C(2)HO(-)和 CH(3)CO(-)阴离子产物的形成，这些产物离子是通过电子能量范围在 6 到 13 eV 的散射共振产生的。在这些产物离子中，只有 O(-)形成了具有任何可测量动能分布的产物，表明这是一个双体离解过程。尽管 CH(3)CO(-)的动能非常低，但在速度切片图像中表现出各向异性，表明 H 原子沿相对于电子束的 180°方向被逐出。其他产物离子的动能分布和角分布都没有各向异性，这表明它们是通过瞬态分子负离子的多次碎裂形成的。O(-)的角分布根据各种分波进行了分析。
