Energy loss straggling for slow ions in an electron gas

Energy – loss straggling of ions with velocity small than Fermi velocity in an electron gas has been evaluated from phase shifts which are determined from nonlinear, density – functional calculations. The results show oscillations in straggling with increasing nuclear charge are correlated with the scattering properties of electrons at Fermi level. The linear behavior of the energy loss with the ion velocity is obtained under the free electron gas (FEG) in the frame of nonlinear density functional theory (DFT) or linear dielectric formalism.