Time- and frequency-domain properties of light emitted in slow ion-atom collisions

We describe light emission from the complex formed during ion-atom collisions, that arises from electronic charge transfer and the related oscillatory dipole of the complex. This is treated in an eikonal/time-dependent Hartree-Fock approach which accounts for coupling of electronic and nuclear motions and generates the time-dependent dipole of the complex. Calculations were done for H⁺+H with a basis set of travelling atomic functions, for collision energies of 100, 250, and 1000 eV, to obtain the energy emitted per solid angle versus both time and the light frequency. Results are presented for the intensity components of the light emitted parallel and perpendicular to the incoming projectile H⁺ velocity. Light emission is found to last several femtoseconds, and to be distributed over ultraviolet frequencies. The intensity of light emitted by the complex H₂⁺ increases as collision energies are lowered.