Effect of the reverse reaction on the experimental determination of energy transfer rate constants

The effect of the reverse reaction in the experimental determination of energy transfer rate constants is re-emphasized. It is shown that the pressure independence of the measured rate constant, frequently used experimentally as an indicator of the absence of reverse reactions, may have more complicated sources like the presence of a third channel of dissipating the excited species. Thus, pressure independence alone is not a reliable indicator of the absence of reverse reactions. The quenching of Ar 3P1 by H2 is used as an illustrative example with the energy transfer rate constant and the rate constant of the reverse reaction estimated using the Born approximation [W. M. Huo, J. Chem. Phys. (preceding paper)].