Stopping power of extended cluster and ion charge distributions in an arbitrarily degenerate electron fluid

The stopping power of an extended charge distribution at any velocity by a free-electron gas is calculated in the random-phase approximation at any degeneracy. Asymptotic expressions are given in the low- and high-velocity range for any charge distribution with spherical symmetry. We pay attention to the determination of the critical distances of pointlike behavior for an extended charge and uncorrelated behavior for two separated charges. The particular cases of randomly orientated dicluster and atomic ion with extended charges distribution are given particular attention