Coulomb explosion following electronic excitation in ion-solid interaction

In atomic collisions in solids by the ions with very strong electronic interaction, it is confirmed that the atomic displacement process is enhanced by electronic excitation. Two experimental results are introduced as examples. The first is the columnar defect formation in a cuprate superconductor Bi₂Sr₂CaCu₂O_x which is irradiated with 3.5 GeV Xe ions, the second is sputtering induced by highly charged ion (HCI) bombardment (Xe^q+; q=15-44). Since there are some indications to show that these phenomena might be the outcome of the Coulomb explosion process, we tried to make a molecular dynamics simulation of the sputtering process based on this Coulomb explosion mechanism. Good agreement between the simulation and experiment was found. For sputtering of electrically conductive materials, the importance of neutralization dynamics of the HCI and the highly charged region in the solid materials was indicated.