The influence functional coefficients that correspond to the QuAPI discretization of the path integral are available in several forms. These are first obtained as time integrals of the appropriate bath correlation function, and can be expressed in the form of frequency integrals involving the spectral density. We have given these coefficients in various forms, suitable for model calculations with a given spectral density, or for simulating processes where the effective harmonic bath is obtained in terms of time correlation functions of the actual polyatomic environment, for factorized or equilibrium initial conditions, and for a shifted bath that corresponds to the diabatic potential surface of the donor.

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