Neutral and anionic CuO2: an ab inito study

By using first-principles calculations within density functional theory via the local density approximation (LDA) and the generalized-gradient approximation (GGA) of Perdew and Wang for exchange and correlation, we calculate the equilibrium structures of CuO2 and CuO2− clusters. In the case of CuO2, three isomers (OCuO linear and two CuO2 complexes, side-on and bent) lie within 0.5 eV, while the negatively charged cluster is most stable as a linear molecule. Our assignment of measured photo-electron spectra features on the basis of the electronic density of states (EDOS) suggests that the bent structure is the most stable among the two forms of CuO2− complexes.