The Vibrational Spectra of CO2+, (CO2)2+, CO2-, and (CO2- Trapped in Solid Neon

Published

September 8, 1999

Author(s)

Warren E. Thompson, Marilyn E. Jacox

Abstract

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 ( ²ς_u⁺) 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 D_2d 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 (D_2d) 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 .

Citation

Journal of Chemical Physics

Volume

111

Issue

No. 10

Pub Type

Journals

Keywords

(CO₂)₂+, (CO₂)₂-, CO₂+, CO₂-

Citation

Thompson, W. and Jacox, M. (1999), The Vibrational Spectra of CO₂⁺, (CO₂)₂⁺, CO₂^-, and (CO₂^- Trapped in Solid Neon, Journal of Chemical Physics (Accessed October 13, 2025)