Low-lying electronic states of the MnS-/0 clusters have been investigated by DFT, RCCSD(T), and NEVPT2 methods. The anionic ground state is predicted to be (7)Sigma(+) while the neutral ground state is confirmed as (6)Sigma(+). The (7)Sigma(+) (6)Sigma(+) transition is proposed to be at the origin of the lowest energy band of the anion photoelectron spectrum. The (7)Sigma(+) -> (6)Pi transition is demonstrated to be responsible for the higher energy band. The Franck-Condon factor simulations for these two ionizations, as based on the NEVPT2 potential energy curves, confirm the experimental broadness of the two bands. (C) 2015 Elsevier B.V. All rights reserved.