Infrared spectra and theoretical studies of the C2O3− anion isolated in solid argon

Abstract

Laser ablation of transition metal targets with concurrent 11 K deposition of CO2/CO/Ar mixtures produces CO2− anion absorption at 1657.0 cm−1 and two additional metal independent absorptions at 1793.7 and 1701.7 cm−1. Isotopic substitution shows that the 1793.7 cm−1 band is due to a C–O stretching vibration and the 1701.7 cm−1 band an antisymmetric CO2 vibration. The UV photolysis and CCl4 doping experiments strongly suggest an anion identification. Based on density functional theory and ab initio calculations of structure and vibrational frequencies, these two bands are assigned to the C–O and antisymmetric CO2 stretching vibrations of the C2O3− anion coordinated between two C atoms with nonplanar Cs symmetry. Our calculations also show that the C2O3− anion is a covalently bound molecule.