Resonant scattering of electrons by molecules

Abstract

11.3. Vibrational excitation of H, at low energies 11.4. Electron scattering by H, near 12 ev . 11.5. Electron scattering by N, near 2 ev . 12.1. Vibrationally excited Rydberg states . 12.2. Long-lived resonances in polyatomic molecules . 13.1. Electron detachment in H-H-collisions , 13.2. Associative detachment in H-Hcollisions at thern 13.3. Ionization in the collisions of two neutral atoms . 13.4. Electronically stable resonances . . 12. Non-adiabatic collision processes . 13. Heavy particle collisions . 14. Conclusions . References .

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

“…These are the well-known dipole-supported states, discussed originally by Fermi andTeller (1947, see also Turner, 1977) and observed in a series of experiments on charge transfer from Rydberg atoms to polar molecules and clusters (Desfranc¸ois et al, 1994a, b, c;Desfranc¸ois et al, 1996;Compton and Hammer, 2001 (Bardsley and Mandl, 1968;Domcke and Cederbaum, 1981;Gauyacq and Herzenberg, 1982).…”

“…The quasi-bound vibrational levels in V res,2 (R) with v 2 ! 1 lie in the electron-molecule continuum and correspond to vibrational Feshbach resonances (VFR, Schramm et al, 1999); they were previously addressed as nuclear-excited Feshbach resonances (Bardsley and Mandl, 1968;Gauyacq and Herzenberg, 1982;Knoth et al, 1989a;Thu¨mmel et al, 1993). In the depicted case, the VFRs can only decay by autodetachment through indirect coupling to the continuum (via kinetic coupling of the two resonance states).…”

Cross sections for 14-eVe-H2resonant collisions: Isotope effect in dissociative electron attachment

“…In order to understand the physical behavior of the crosssection curves, we assume a narrow resonance and use the semiclassical Wentzel-Kramers-Brillouin (WKB) approximation to express the DEA cross sections as [3] (see also Refs. [12] and [13])…”

“…Theoretically, the process of dissociative electron attachment to H 2 (or any of its heavier isotopes) is understood [3] * r.celiberto@poliba.it † r.janev@fz-juelich. …”

“…The two peaks at ∼3.75 and 14 eV are observed to be quite sharp while the third peak at ∼10 eV is rather broad. It has been recognized [3][4][5][6][7][8][9][10], that the peaks at ∼3.75 and 10 eV correspond to the formation of X 2 + u and B 2 + g resonant states of H 2 − , which asymptotically dissociate into H(1s) and H − (1s 2 ), while the sharp peak at ∼14 eV corresponds to the formation of intermediate 2 + g excited electronic Rydberg state of H 2 − , which dissociates into H(n = 2) and H − (1s 2 ). The potential curves of these three resonant states have different characteristics which lead to DEA cross sections that exhibit entirely distinct behaviors as the electron energy is varied.…”