Some Systematics in Electron Scattering Cross Sections

Operation of thermonuclear reactors will require knowledge of numerous cross sections for electron interaction with atoms and molecules, largely unknown at present and difficult for experiments. Theory is needed, but first it has to be verified on laboratory-accessible targets. A few working hypotheses and systematic approaches for various electron scattering processes are recommended. We discuss briefly analogies between total cross sections for scattering on nonpolar (BF₃, CO₂), polar (H₂O, NH₃, PF₃), reactive (BCl₃, HCl), and hexafluoride (SF₆, WF₆) molecules. For partial cross sections (ionization, elastic, electronic excitation), we search for some partitioning schemes. Similarly, we treat the vibrational excitation at shape resonances in linear triatomic molecules (N₂O, CO₂, OCS). Electron attachment for targets such as CCl₄ or CF₃I rises quickly toward the zero-energy limit; semiempirical approaches fail, but new theories work well. The paper, in general, shows ways to multitask construction of cross sections rarely measured in laboratories.