The collision energy dependence of chemiluminescence, and its polarization relative to the initial velocity vector k, has been determined for MnO*(A(6) Sigma(+)) product from the Mn + O-2 reaction in the range 0-1500 kJ mol(-1). Analysis of the excitation function by the multiple line-of-centers approach indicates that three parallel processes, attributed to a(4)D(J), z(8)P(J) (perhaps), and a(6)D(J) atoms, contribute. All seem to involve a significant excess barrier and a forward transition state shift with increasing collision energy, suggesting that reaction proceeds via inner ionic-covalent curve crossings at short internuclear distances. The measured alignments are relatively modest, indicating a predominant contribution to MnO rotation from O-O recoil in a nonlinear Mn-O-O configuration.