Wake effects on charge states and molecular-axis orientations of fast diatomic molecular ions in solids
尾流效应对快速双原子分子离子在固体中电荷态及分子轴取向的影响

We have studied the wake effects on charge states and molecular axis orientations of diatomic molecular ions, such as N 2 +, moving in solids. Based on the linear response dielectric theory with the local dielectric function, the dynamic interacting potential is expressed as a sum of the symmetric screened Coulomb potential and the asymmetric wake potential. The equilibrium charge state of individual ions in the molecular ions is determined by a variational approach to the total energy of bound electrons in the molecular ions. The Coulomb explosion patterns of the molecular ions are also simulated by solving equations of motion for individual ions. It has been found that, in the initial stages of penetration through the solid, the charge of the trailing ion oscillates with increasing penetration depth due to the wake effects in the dynamic interaction potential, while the charge of the leading ion increases monotonically towards the value characteristic of an isolated ion at the same speed. Moreover, the molecular\|axis orientations incline towards the direction of the projectile's velocity.