title: An IR study of (CO2)(+)n (n=3-8) cluster ions in the 1000-3800 cm-1 region.
abstract: Infrared photodissociation (IRPD) spectra of carbon dioxide cluster ions, (CO(2))(n) (+) with n=3-8, are measured in the 1000-3800 cm(-1) region. IR bands assignable to solvent CO(2) molecules are observed at positions close to the vibrational frequencies of neutral CO(2) [1290 and 1400 cm(-1) (nu(1) and 2nu(2)), 2350 cm(-1) (nu(3)), and 3610 and 3713 cm(-1) (nu(1)+nu(3) and 2nu(2)+nu(3))]. The ion core in (CO(2))(n) (+) shows several IR bands in the 1200-1350, 2100-2200, and 3250-3500 cm(-1) regions. On the basis of previous IR studies in solid Ne and quantum chemical calculations, these bands are ascribed to the C(2)O(4) (+) ion, which has a semicovalent bond between the CO(2) components. The number of the bands and the bandwidth of the IRPD spectra drastically change with an increase in the cluster size up to n=6, which is ascribed to the symmetry change of (CO(2))(n) (+) by the solvation of CO(2) molecules and a full occupation of the first solvation shell at n=6.
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Japan. y-inokuchi@hiroshima-u.ac.jp
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Inokuchi
authors.forename: Azusa
authors.initials: A
authors.lastname: Muraoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagata
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ebata