Structural and Electronic Properties of ConC3−/0and ConC4−/0(n=1−4) Clusters: Mass-Selected Anion Photoelectron Spectroscopy and Density Functional Theory Calculations

We investigated the structural evolution and electronic properties of ConC3-/0 and ConC4-/0 (n = 1-4) clusters by using mass-selected photoelectron spectroscopy and density functional theory calculations. The adiabatic and vertical detachment energies of Co1-4C3 and Co1-4C4- were obtained from their photoelectron spectra. By comparing the theoretical results with the experimental data, the global minimum structures were determined. The results indicate that the carbon atoms of ConC3-/0 and ConC4-/0 (n = 1-4) are separated from each other gradually with increasing number of cobalt atoms but a C-2 unit still remains at n = 4. It is interesting that the Co2C3- and Co2C4- anions have planar structures whereas the neutral Co2C3 and Co2C4 have linear structures with the Co atoms at two ends. The Co3C3- anion has a planar structure with a Co2C2 four-membered ring and a Co3C four-membered ring sharing a Co-Co bond, while the neutral Co3C3 is a three-dimensional structure with a C-2 unit and a C atom connecting to two faces of the Co-3 triangle.