The Vibrational Spectra of CO2+, (CO2)2+, CO2-, and (CO2- Trapped in Solid Neon
Warren E. Thompson, Marilyn E. Jacox
When a Ne:CO2 mixture is subjected to Penning ionization and/or photoionization by neon atoms in their first excited states, between 16.6 and 16.85 eV, and the products are rapidly frozen at approximately 5 K, the infrared spectrum of the resulting deposit includes absorptions assigned to CO2+, (CO2)2+, CO2 , and (CO2)2 . The lowest ( 2ςu+) Renner component of the bending fundamental of CO2+ trapped in a neon matrix appears near the gas-phase band center, but other Renner components are undetectable. Absorptions of a photolabile product correspond to the recently identified CO-stretching fundamentals of (CO2)2+. Weak infrared absorptions at 1253.8 cm 1 and 714.2 cm 1 are assigned to υ1 and υ2 of CO2 , respectively, and a moderately intense absorption at 2894.7 cm 1 is assigned to the υ1 + υ3 combination band of that product. As in other recent argon- and neon-matrix studies, two weak infrared absorptions can be assigned to the two infrared-active OCO-stretching fundamentals of the D2d structure of (CO2)2 . Detailed isotopic substitution studies support all of these assignments. A weak absorption near the CO2 bending fundamental, for which isotopic substitution data are incomplete, may be contributed either by a second fundamental of (CO2)2 (D2d) with b2 symmetry or by a weakly interacting (CO2)n CO2 complex. Such ion-molecule complexes contribute other absorptions near υ3 of CO2 and of CO2 .
and Jacox, M.
The Vibrational Spectra of CO<sub>2</sub><sup>+</sup>, (CO<sub>2</sub>)<sub>2</sub><sup>+</sup>, CO<sub>2</sub><sup>-</sup>, and (CO<sub>2</sub><sup>-</sup> Trapped in Solid Neon, Journal of Chemical Physics
(Accessed November 29, 2023)