“…Various theoretical models have appeared in the literature, and many types of experiments have been performed, in order to determine the energy dependence of the magnitude of the cross sections involved in the elastic, inelastic, ionizing, and dissociative processes resulting from the collision of an electron with a molecule. − These phenomena are induced by the potential interaction between the electron and the target molecule. − It has been found desirable for understanding the essential physics of the scattering phenomenon to divide the process into resonant and direct. , When the time-dependent amplitude of the projectile electron wave function does not increase significantly in the vicinity of a small molecule , or a molecular site of a large molecule, the scattering process is considered to be direct; otherwise, it is resonant. With dependence on electron energy, elastic and inelastic scattering can proceed by both mechanisms. ,− Dissociative electronically excited states can break bonds, − but below the energy threshold for electronic excitation, only dissociative electron attachment (DEA) can dissociate molecules. , Since at resonance energies, the electron interacts more strongly with the target and for a longer time, bond dissociation can be considerably increased by TMAs that cause maxima in the yield functions of molecular damages . In a large molecule, such as oligonucleotides and DNA, both direct and resonance scattering processes occur and can lead to bond cleavage. , Nonresonant cross sections, generally, show a smooth, slowly varying, energy dependence. − This nonresonant behavior can be seen in the yield functions of neutral radicals. − In the case of short DNA strands, the LEE yield functions of neutral species provide good examples of resonance maxima superimposed on a smoothly varying background caused by direct scattering. , …”