JILA and Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0440 , United States.
Center for Joint Quantum Studies and Department of Physics, School of Science , Tianjin University , 300072 Tianjin , P. R. China.
J Phys Chem A. 2019 Oct 10;123(40):8562-8570. doi: 10.1021/acs.jpca.9b07780. Epub 2019 Sep 26.
We report the kinetic energy distributions in electron autodetachment from nitroethane, 1-nitropropane, and 1-nitrobutane anions upon laser excitation of CH stretching modes measured using velocity map electron imaging. In striking contrast to the case of nitromethane, the kinetic energy distributions show almost no distinct vibrational features, and they can be described by thermionic emission, relating the shape of the distributions to the electron capture cross section of the neutral molecule. The data suggest that a classical description is warranted above ca. 20 meV electron kinetic energy. At lower energies, quantum effects suppress the attachment cross section.
我们报告了硝基乙烷、1-硝基丙烷和 1-硝基丁烷阴离子在 CH 伸缩模式激光激发下通过速度图电子成像测量的电子自脱附的动能分布。与硝基甲烷的情况形成鲜明对比的是，动能分布几乎没有明显的振动特征，它们可以用热电子发射来描述，分布的形状与中性分子的电子俘获截面有关。数据表明，在约 20 毫电子伏特以上的电子动能下，经典描述是合理的。在较低的能量下，量子效应会抑制附着截面。
