DUAL MECHANISM FOR CO(A(1)PI)-CO(X(1)SIGMA(-TRANSFER - AN OODR-MPI SPECTROSCOPIC STUDY()) ROVIBRONIC ENERGY)

The highly versatile OODR-MPI technique is used, mostly without resort to isotope tagging, to study the quantum state specific rovibronic en ergy transfer between molecules of the same species, specifically CO(A )-CO(XJ. Two types of rovibronic energy transfer mechanisms are found to be prevailing and are differentiated experimentally, i.e., the long range near resonant dipole-dipole interactions and the short range ex ciplex formation. The first type is characterized, at first unexpected ly, by its compliance to the selection rules of optical dipole transit ions, Delta J = 0, +/-1 and parity + <----> -. Numerical computation p rocedures are presented for the calculation of rovibronic energy trans fer cross-sections when the two types of mechanism are operating concu rrently. The computed results and their variation with J are in good a ccord with the experiments .