Breaking of a polymer – multidimensional classical transition state theory and beyond

When a mechanical force stretches a polymer molecule, each bond in the chain becomes metastable. The polymer breaks by the escape of any bond from this state. Multidimensional classical transition state theory is used to calculate the frequency factor for the rate of breaking (νcross). Using a continuum approach, we also calculate the frequency factor (νsep) associated with the rate of separation of the two broken ends from one another. The net frequency factor is taken to be the harmonic mean of νcross and νsep. While our results are lower than those of simple transition state theory, it is orders of magnitude larger than the results of the available simulations. This difference is ascribed to the friction that has been included in the simulations.