Cluster stopping power for an electron gas at finite temperatures: calculations for hydrogen and water clusters

Abstract

A formalism for the stopping power of atomic clusters moving in an electron gas at finite temperature is presented. Calculations for diatomic, triatomic and larger clusters are performed, for cluster velocities smaller than the Fermi velocity of the target electrons. The dependence of the cluster stopping power on cluster orientation is more significant for small clusters at low temperatures. The interference effects on the stopping power of large clusters are described in terms of the pair correlation function of the cluster components. Specific results are given for clusters of hydrogen and water molecules. The authors obtain an enhancement of the cluster stopping power, which varies with temperature due to changes in the screening conditions. For large molecular clusters the intermolecular vicinage function is negative, and at low temperatures diminishes the stopping power enhancement due to intramolecular contributions.