Several formally exact expressions for quantum mechanical rate constants (ie, bimolecular
reactive cross sections suitably averaged and summed over initial and final states) are
derived and their relation to one another analyzed. It is suggested that they may provide a
useful means for calculating quantum mechanical rate constants accurately without having
to solve the complete state‐to‐state quantum mechanical reactive scattering problem.
Several ways are discussed for evaluating the quantum mechanical traces involved in these …