Fig. 3: VMI images.

Coincidence VMI images of Ar+ and HeAr+ (a, d) and coincidence electrons (b, e). Ionic data are presented on a log scale to emphasize the outer circular feature which is the main interest of this paper. c, f Electron VMI images after rotation to the ionic frame of reference, where θ is defined as the relative angle between the 2D velocities of the electron and the ion.