Polyatomic molecules, resonant electron scattering

Resonant Electron Scattering and Anion States in Polyatomic Molecules... 

K. D. Jordan and P. D. Burrow, in Photon, Electron, and Ion Probes of Polymer Structure and Properties, ACS Symposium Series Vol. 162, American Chemical Society, 1981 chapter 1, pp. 1-10, Resonant Electron Scattering and Anion States in Polyatomic Molecules. 

Evidence for resonances in the cross sections for electron scattering from polyatomic molecules. Including hydrocarbons, can be found In the literature as far back as the late 1920 s (1,2). The authors of these papers, however, were unaware that the pronounced low energy peaks in the cross sections of molecules such as ethylene and acetylene were due to temporary negative Ion formation. Haas (3), In 1957, was apparently the first to observe that strong vibrational excitation accompanied such a peak, and to Invoke an unstable negative Ion complex as the means through which the excitation takes place. 

In this paper we first review the characteristics of resonances in molecules, and then discuss recent experimental results in polyatomic systems, with examples chosen to illustrate the types of information that can be provided by ETS. We discuss some of the problems uncovered, and the role that other electron scattering methods and theory could play in solving these problems. 

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