title: Complexation of allyl radicals and hydrochloric acid in helium nanodroplets.
abstract: Infrared spectra of the allyl radical-HCl complex in superfluid helium nanodroplets have been recorded in the IR frequency range of 2750-3120 cm(-1). Six fundamental bands were observed, five of which have been assigned to the C-H stretch vibrations of the allyl radical. No additional CH bands were observed upon the binding of HCl. The band at 2800.3 cm(-1) can unambiguously be assigned to the bound HCl stretch, which is red-shifted by 106 cm(-1) compared to that of the free HCl. Stark spectra and pickup curves were recorded and support our assignment. In accompanying ab initio calculations, we found four equivalent minima and computed a two-dimensional potential energy surface for the HCl positioning on the allyl radical plane at the CCSD(T)/TZVPP level. Based on our findings, we conclude that the ground-state structure of the complex shows two energetically equivalent T-shaped minimum structures. Because of small barriers between the two minima, a delocalization of the HCl is anticipated.
authors.affiliation: Department of Physical Chemistry II, Ruhr-University Bochum , 44801 Bochum, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Leicht
authors.forename: Daniel
authors.initials: D
authors.lastname: Habig
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schwaab
authors.forename: Martina
authors.initials: M
authors.lastname: Havenith