Radical species of the nucleic acid bases (NABs) play a primary role in radiation damage and electron transfer processes of DNA. In the present work, a novel QM/MM model for simulating molecular systems in the liquid phase has been applied to study the microsolvation of the uracil anion radical in comparison with the parent molecule. Moreover, we have analyzed the vertical detachment energy as a function of structural intramolecular and intermolecular fluctuations in order to find molecular modes that may possibly promote the electron transfer process. (C) 2010 Elsevier B.V. All rights reserved.