Lifetime of a hydrogen bond in aqueous solutions of carbohydrates

In this paper we present a novel method of calculating hydrogen bond lifeti mes that circumvents many of the problems encountered with existing methods . The method is based on a three-level model in which the pair of molecules are hydrogen bonded, not hydrogen bonded, or in an intermediate state; hyd rogen bonds are identified within the intermediate stale according to how t he dimer enters and leaves the intermediate state. An effective dimer inter action energy is used to define these three stales. The hysteresis introduc ed by this definition makes it possible to distinguish between large-amplit ude vibrations in the hydrogen-bonding coordinates and real bond-breaking e vents. The method is applied to a dilute aqueous glucose solution and shown to generate hydrogen bond lifetimes that are in accord with both chemical intuition and experiment.