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Based on the Elastically Collective Nonlinear Langevin Equation theory ofbulk relaxation in glass-forming liquids, and our recent ideas of howinterface-nucleated modification of caging constraints are spatiallytransferred into the interior of a thick film, we present a force-based theoryfor dynamical gradients in thick films with one vapor interface that includescollective elasticity effects. Quantitative applications to the foundationalhard sphere fluid and polymer melts of diverse fragilities are presented. Wepredict a roughly exponential spatial variation of total activation barrierwhich is non-perturbatively modified to ~10 particle diameters into film. Thisleads to prediction of a reduced alpha relaxation time gradient of a doubleexponential form characterized by a nearly constant spatial decay length, inqualitative accord with simulations. These spatially heterogeneous changes ofthe temperature variation of the alpha time result in a large and long-rangegradient of the local glass transition temperature. An average interfaciallayer thickness relevant to ensemble-averaged dielectric and other experimentsis also computed. It is predicted to be rather large at the bulk glasstransition temperature, decreasing roughly linearly with heating. Spatiallyinhomogeneous power law decoupling of the alpha relaxation time from its bulkvalue is predicted, with an effective exponent that decays to zero withdistance from the free surface in a nearly exponential manner, trends which arein qualitative accord with recent simulations. This behavior and the doubleexponential alpha time gradient are related and can be viewed as consequencesof an effective quasi-universal factorization of the total barrier in filmsinto the product of its bulk temperature dependent value times a functionsolely of location in the film.

Influence of Longer Range Transfer of Vapor Interface Modified Caging Constraints on the Spatially Heterogeneous Dynamics of Glass-Forming Liquids