Electron attachment to molecules in a cluster environment

Abstract

Low-energy dissociative electron attachment (DEA) to the CF 2 Cl 2 and CF 3 Cl molecules in a water cluster environment is investigated theoretically. Calculations are performed for the water trimer and water hexamer. It is shown that the DEA cross section is strongly enhanced when the attaching molecule is embedded in a water cluster, and that this cross section grows as the number of water molecules in the cluster increases. This growth is explained by a trapping effect that is due to multiple scattering by water molecules while the electron is trapped in the cluster environment. The trapping increases the resonance lifetime and the negative ion survival probability. This confirms qualitatively existing experiments on electron attachment to the CF 2 Cl 2 molecule placed on the surface of H 2 O ice. The DEA cross sections are shown to be very sensitive to the position of the attaching molecule within the cluster and the orientation of the electron beam relative to the cluster.

Theory of dissociative electron attachment: Biomolecules and clusters

“…The present theory produces the cross section enhancement due to the cluster environment, as was already established in Ref. [40], although quantitatively results are somewhat different. An accurate calculation of the vertical attachment energy shifts is required for more reliable results for the DEA cross sections.…”

“…6 we present the DEA cross sections for the CF 3 Cl molecule embedded in a water hexamer cluster for the geometry described in Ref. [40]. The cross section is very sensitive to the vertical attachment energy shift due to the cluster environment.…”

“…Because of some uncertainties in this quantity, we present results of two calculations: one with 07001-p. 7 EPJ Web of Conferences 6 cluster for the geometry of Ref. [40] for two solvation energies, 0 and −0.2434 eV.…”

“…[40]. The 2 A 1 contribution to the elastic electron scattering by CF 3 Cl was calculated within the framework of the resonance R-matrix model [45] with some adjustments to get a better agreement with ab initio calculations [46,47].…”

“…[40] we applied the multiple-scattering theory [14,15,41] to calculations of attachment amplitude in the presence of a water cluster. The expressions we used incorporated the multiple scattering effects only partly.…”