Resonance and Threshold Phenomena in Low-Energy Electron Collisions with Molecules and Clusters

Stable Valence Anions of Nucleic Acid Bases and DNA Strand Breaks Induced by Low Energy Electrons

“…On the other hand, at lower energies the cleavage process is due to the formation of transient resonance anions [1,2,[15][16][17][18]. Thus, the SSB and DSB maxima on the yield function observed around 8 and 10 eV (Figure 21-3), [12].…”

“…respectively, may be interpreted as originating from resonance anions. The strand break yields as a function of electron impact energy peaks near the threshold for electronic excitation of DNA constituents which suggests that the cleavage process induced by electrons of 8-10 eV is initiated through the short-lived core-excited anion states [16]. The core-excited resonances usually have relatively long lifetimes which promote their dissociation [15].…”

“…An electron transfer mechanism involving shape resonances could also explain, at least partially, strand break formation by LEEs from the 8-10 eV range. First, for shape resonances the lifetime is usually too short above 5 eV for dissociation [16,24] and electron detachment or transfer is highly probable. Second, Grandi et al [25] have reported the formation of a shape resonance for uracil near 9 eV.…”

Elastic and inelastic low-energy electron collisions with pyrazine

“…[2][3][4] Three π * electron resonances have been found experimentally in the four DNA bases and in uracil. 5,6 It has been proposed [6][7][8][9][10][11] on the basis of experimental evidence, that the lowest-energy features (below 3 eV) in the dissociative electron attachment (DEA) spectra of the bases do not correspond directly to any of these π * resonances but are rather caused by the formation of vibrational Feshbach resonances 11,12 and by an interaction, mediated by nuclear motion, between the π * resonances and a possible σ * resonance occurring in this energy region.…”

Low-energy electron elastic scattering cross sections for excited Au and Pt atoms

“…Low-energy electron collisions with atoms, molecules and clusters, resulting in negative ion formation as intermediate resonances, provide deep insight into quantum dynamics and imply the dominance of a very few partial waves in the collision [2]. The mechanism through which low-energy electron scattering deposits energy and induces chemical transitions is attributed to the formation of temporary negative ionic states and their properties [3]. Various theoretical investigations have demonstrated through comparisons with measurements the vital importance of the core-polarization interaction in low-energy electron scattering from atoms and molecules [4][5][6][7][8][9][10][11][12].…”