Cyclic and linear MnC2(-/0) clusters have been theoretically studied. The (7)A(1) and (6)A(1) states of the cyclic isomer are calculated to be the ground states of the anionic and neutral cluster, respectively. All observed bands in the experimental photoelectron spectra of MnC2- could be assigned to the cyclic isomer. The X band is ascribed to an ionization during which an electron is detached from a nonbonding 4s4p hybrid orbital. The higher bands in the spectra are the result of ionization processes in which an electron from the nonbonding HOMO of the C-2(2-) ligand is removed. (C) 2013 Elsevier B. V. All rights reserved.