FIG. 4.

Delay-dependent ion yield in channel III for different iodine charge states from (a) iodomethane and (b) difluoroiodobenzene molecules. The data points are obtained by integrating all recorded ions of each species within a TKER range of 0–2.5 eV for CH₃I and for a TKER range of 0–1.5 eV for DFIB, recorded using the CCD camera (gray circles) or the PImMS camera (colored symbols). To extract the center of the step functions, a Gaussian cumulative distribution function was fitted to the PImMS data, as shown by the solid lines. For better visibility, the yields for the different charge states are offset on the vertical axis. Negative delays correspond to the XUV pulse arriving first and positive delays to the UV pulse arriving first. The large inverted triangles indicate the calculated critical distances for internuclear charge transfer resulting from the over-the-barrier model (see the text). (c) Delay-dependent ion yield of the two components III a (integrated over the TKER range of 0–1.5 eV) and III b (1.5–2.5 eV) in the I³⁺ channel in CH₃I, recorded using the CCD camera.