Multiple chemiluminescent channels in the reaction Mn + SF6 → MnF + SF5

Five different MnF* emitting states - A7Π, e5Σ+, d5Π, c5Σ+, and b5Π - have been observed from collisions between SF6 molecules and a pulsed, laser-ablated beam of Mn atoms. The various excitation functions, measured up to nominal collision energy ET0 = 2000 kJ mol-1, have been modeled by the multiple line-of-centers approach. The analysis indicates that MnF*(A7Σ+) is predominantly formed on a single potential surface, with probable progenitor Mn*(z8PJ); the e5Σ+, d5Π, and c5Σ+ states are formed via three common potential surfaces, with likely reagent state Mn*(a6DJ), while the a6DJ state is also likely to be the progenitor of MnF*(b5Π). Partial depletion of the b5Π state at high energy seems to be accompanied by enhanced yield of the other emitters. All reactions seem to be characterized by a shift forward in transition state location with increasing collision energy. The results suggest an electron jump barrier at short internuclear distances, forced outward at higher collision energies due to lack of time for the SF6 to distort to the equilibrium geometry of SF6-.