Nonperturbative corrections to the Kahler potential

We present the results of a detailed investigation into the consequences of adding specific string motivated non-perturbative corrections to the usual tree level Kahler potential in dilaton dominated scenarios. The success of the model is judged through our ability to obtain a realistic vacuum expectation value for the dilaton (ReS)similar to 2, corresponding to the true minima of the scalar potential and being associated with a reasonable value for the supersymmetry breaking scale via the gravitino mass. The status of the so-called moduli problem is also reviewed in each of the Ansatze studied. Those include previous proposals made in the context of both the chiral and the linear multiplet formalisms to describe gaugino condensation, and a new Ansatz which shows explicitly the equivalence between the two.