The aim of this paper is to demonstrate that the Coulomb barrier has variations in both time and space. Further, in this paper, we have taken the interaction between deuteron-optical photons, we want to clarify this point, of course, these photons have a vibrational frequency of interest because it was discovered that the interaction between photons and deuterons causes the Coulomb barrier is not static, that has of oscillations in different directions within the lattice. So we can conclude that this phenomenon of cold fusion that breaks new ground in modern nuclear physics. In recent years, over 20 years, have seen thousands of experiments and theoretical models to explain the phenomenon of fusion at low energy (LENR) in specialized heavy hydrogen systems. We can say that a new possible way to obtain nuclear energy without waste is emerging. Nevertheless in spite of experimental contributions, the theoretical framework is not known. In this work, we try to explain the deuteron-deuteron reactions within palladium lattice by means of the coherence theory of nuclear and condensed matter. The coherence model of condensed matter affirms that within a deuteron-loaded palladium lattice there are three different plasmas: electrons, ions and deuterons plasma. Then, according to the loading percentage x = D/Pd, the ions deuterium can take place on the octahedrical sites or in the tetrahedral in the (1,0,0)-plane. In the coherence theory it is called beta-plasma the deuterons plasma in the octahedral site and gamma-plasma which in tetrahedral. We propose a general model of effective local time-dependent deuteron-deuteron potential, that takes into account the electrons and ions plasma oscillations. The main features of this potential are extracted by means of many-body theory considering the interaction deuteron-phonon-deuteron. In fact the phonon exchange produces a attractive component between two deuteron within the D-2 molecular. This attractive force is able to reduce the inter-nuclear distance from about 0.7 to 0.16 angstrom. It means that the lattice strongly modifies the nuclear environment with respect to free space. In this way according to deuterons energy, loading percentage and plasma frequency we are able to predict high o low tunneling probability. The fusion rates (s(-1)) computed vary from 10(-70) to 10(-17) and also a set of other mechanism, which could be enhanced these values, are proposed. In this way we hope that by means of this approach in the future will be possible to realize and control the nuclear exothermic reactions that take place in the condensed matter in order to obtain clean energy. (C) 2012 ISCMNS. All rights reserved.