Binding of charged particles in lattice defects

Two charged particles will bind in the presence of a lattice defect of radius a. We use random-phase-approximation screening to compute the interaction between the charged particles for several values of rs, which determines the electron density in the defect. Due to the presence of screening, the distance between the bound particles reaches a minimum at an optimum defect size a*. If the charged particles are deuterons, the lifetime of the bound state before fusion is a minimum for a lattice defect of this size. Under the most optimistic conditions of rs=2, the minimum lifetime still exceeds 1080 sec, much too large to explain the experimental measurements.