The geometry of the chlorine dioxide anion : Ab initio calculation and Franck–Condon analysis

Geometry optimization and harmonic vibrational frequency calculations were performed on the X ∼ 2 B 1 state of ClO2 and X ∼ 1 A 1 state of ClO 2 - . The electron affinity energies of ClO2 were calculated up to CCSD(T) level. Franck–Condon analyses and spectral simulations were carried out on the ClO 2 ( X ∼ 2 B 1 ) – ClO 2 - ( X ∼ 1 A 1 ) photodetachment process. In addition, the equilibrium geometry parameters, r(ClO) = 1.567 ± 0.002 Å and ∠(OClO) = 116.5 ± 0.5°, of the X ∼ 1 A 1 state of ClO 2 - , were derived in the spectral simulation. Our conclusions regarding the anion geometry suggest a reinterpretation of the results of Gilles et al. [M.K. Gilles, M.L. Polak, W.C. Lineberger, J. Chem. Phys. 96 (1992) 8012].