Chemiluminescent reactions of manganese with fluorine: Influence of dynamics on product energy partitioning in vibration and rotation of MnF*(b,c).

Chemiluminescent exit channels of Mn+F2-->MnF*+F were investigated using the molecular beam technique in a beam-gas configuration with an array detector. Two uncongested regions, corresponding to MnF transitions c5Sigma+(b)-a5Sigma+(b) and b5Pi(i)(int)-a5Sigma+(b) were fit for vibrational and rotational populations, which were used to develop a microscopic reaction mechanism for these chemiluminescent exit channels. In both MnF* electronic states, significant vibrational excitation but little rotational excitation was found. Significant vibrational excitation has been attributed to early energy release as Mn loses an electron at long range to the lowest unoccupied molecular orbital on F2. The incipient bond is strengthened as backbonding from the F2- to Mn+ increases the covalent character of the intermediate. Finally, no strict geometric constraints are placed on the exit channel and hence there is no significant repulsive energy release into product rotation. Our proposed mechanism exhibits dynamic control in that the course of the reaction is determined by both geometric factors and dynamic factors.