Modelling the directional and energy dependence of 5-10Â keV Ar+ ion-induced secondary electron yields from Cu crystals

► Directional Ar+-induced electron yields from Cu are modelled by molecular dynamics. ► The critical Ar-Cu apsidal distance for electron emission is 0.47 ± 0.03 Å. ► The model describes the energy dependence of Ar+-Cu electron yields. ► The spatial distributions of hard inelastic Ar+-Cu collisions are described.