Eur. Phys. J. D 35, 217-224 (2005)
https://doi.org/10.1140/epjd/e2005-00189-2

Electron capture by HCl trimers: an ab initio study

Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada

Corresponding author: ^a armstron@ucalgary.ca

Received: 4 April 2005
Revised: 26 May 2005
Published online: 19 July 2005

Abstract

The structures and energies of three neutrals and four different anions formed by HCl trimers have been examined by theoretical calculations at MP2 and CCSD(T) levels with large basis sets. In order of increasing binding energy for three HCl molecules, the neutrals are: the Y-shaped species, an open chain Z-shaped form and the cyclic C_3h form. Dipole bound anion states are possible for both the Z and Y neutrals, but the DBS of the latter is likely to be short lived. The threshold energies for dissociative attachment (DA) of an electron in the reaction: e^- + (HCl)₃ → H^• + Cl(HCl)₂^- at the CCSD(T) level are 0.0 and 0.06 eV, respectively for the Y and Z forms. The cyclic species has no dipole moment and does not attach thermal electrons. The structure of the D_3h solvated electron (SE) type trimer anion, was also investigated. Although the structure provides for a high electron affinity (0.33 eV relative to the cyclic trimer) it was unstable and rearranged into a ClH·ClH^•HCl^- (SE(2+1)) species. The latter has an EA of 0.59 eV. Vertical detachment energies were also found for these structures. The EAs and vertical detachment energies of the four HCl anion species are discussed and compared to the corresponding species of HF.