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

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 t wo additional metal independent absorptions at 1793.7 and 1701.7 cm(-1). Is otopic substitution shows that the 1793.7 cm(-1) band is due to a C-O stret ching vibration and the 1701.7 cm(-1) band an antisymmetric CO2 vibration. The UV photolysis and CCl4 doping experiments strongly suggest an anion ide ntification. Based on density functional theory and ab initio calculations of structure and vibrational frequencies, these two bands are assigned to t he C-O and antisymmetric CO2 stretching vibrations of the C2O3- anion coord inated between two C atoms with nonplanar C-s symmetry. Our calculations al so show that the C2O3- anion is a covalently bound molecule. (C) 2000 Ameri can Institute of Physics. [S0021- 9606(00)00216-6].