Dicluster stopping in a degenerate electron gas

In this paper we report on our theoretical studies of various aspects of th e correlated stopping power of two pointlike ions (a dicluster) moving in c lose but variable vicinity of each other in some metallic target materials, the latter being modeled by a degenerate electron gas with appropriate den sities. Within the linear-response theory we have made a comprehensive inve stigation of correlated stopping power, vicinage function and related quant ities for a diproton cluster in two metallic targets, aluminum and copper, and present detailed and comparative results for three approximations to th e electron gas dielectric function, namely, the plasmon-pole approximation without and with dispersion as well as with the random-phase approximation. The results are also compared, wherever applicable, with those for an indi vidual projectile.