V. Zengin, B. Joakim Persson, K.M. Strong and R.E. Continetti, "Study of the Low-Lying Electronic States of CCO by Photoelectron Spectroscopy of CCO- and Ab Initio Calculations", J. Chem. Phys. 105, 9740-9747 (1996).
The low-lying electronic states of CCO have been investigated by photoelectron spectroscopy of CCO- at wavelengths of 266 and 355 nm in conjunction with ab initio calculations. Photodetachment is observed to occur to the 3*-, 3*, 1* and 1*+ electronic states of CCO. This marks the first observation of the low-lying singlet states. A revised value for the electron affinity of CCO is found to be 2.289 +/- 0.018 eV. These results are compared with CASPT2 ab initio calculations of the energetics and structure of the ground and excited states of CCO and CCO-. Using the measured electron affinity of CCO, the heats of formation *fH0298(CCO) = 3.99*0.20 eV and *fH0298(CCO-) = 1.67*0.20 eV are determined. In addition, the C-C bond dissociation energies in CCO and CCO- are determined, as well as the H-CCO bond energy in HCCO.