The lowest-lying quartet electronic states of MnC, correlating with the three lowest-lying atomic dissociation channels, were investigated theoretically for the first time, with the state-of-the-art multireference configuration interaction (MRCI) approach, based on complete-active-space self-consistent-field (CASSCF) wave functions and extensive basis sets. Excitation energies, equilibrium internuclear distances, dissociation energies, and spectroscopic constants for eleven electronic states will be reported. Franck-Condon factors, Einstein coefficients, and radiative lifetimes for the first excited state will also be presented. (c) 2005 Elsevier B.V. All rights reserved.