The IR (810 nm) -VIS (405 nm) pump-probe experiments were carried out at the permanent CAMP end-station at beamline BL1 at the free-electron laser in Hamburg (FLASH) facility. A Ti:Sa laser system produced pulses at 810 nm. The pulses were then split into two components with a beamsplitter in a ratio of 75:25. Most of each pulse was used as an IR pump, and a part of each pulse went to the second harmonic generation (SHG) to produce a weaker VIS probe pulse of 405 nm. The duration (full width at half maximum, FWHM) of the IR pulse was 60 fs, while the duration of the VIS pulse was estimated to be less than 150 fs. We measured the ion yield produced as a function of pump-probe delay time. The arrival time of the probe pulse was varied from -1 ps to +1 ps in 15 fs steps relative to the pump pulse using a mechanical delay stage.