We have calculated the relative stability as well as UV spectra of a few ClO isomers. In agreement with previous investigations we find that ClOOCl and ClClO are the most likely ground-state chlorine oxide dimers and that they have little biradical character. Using the RPA method, we have calculated UV excitation energies and oscillator strengths and conclude that the UV spectrum of ClOOCl below 6 eV (∼200 nm) is too weak to be readily observed. The consequences of the present calculations for earlier measurements of UV absorption that were assigned to ClO species are discussed.
