Studies of charge-charge (ion-ion, ion-electron, and electron-electron) coupling properties for ion impurities in an electron gas are carried out on the basis of a regularized electron-ion potential without short-range Coulomb divergence. This work is motivated, in part, by questions arising from recent spectroscopic measurements revealing discrepancies with present-day theoretical descriptions. Many of the current radiative property models for plasmas include only single electron-emitter collisions and neglect some or all charge-charge interactions. A molecular-dynamics simulation of dipole relaxation is proposed here to allow proper account of many electron-emitter interactions and all charge-charge couplings. As illustrations, molecular-dynamics simulations are reported for the cases of a single ion embedded in an electron plasma and for a two-component ion-electron plasma. Charge-charge coupling effects are discussed for hydrogen-like Balmer alpha lines at weak coupling conditions.