Influencing the formation of H₃⁺ from ethane using shaped ultrafast laser pulses

Using both closed- and open-loop control to tailor ultrafast laser pulses, we study the ratio of D₂H⁺ to D₃⁺ produced from the D₃C-CH₃ isotopologue of ethane, which selects between trihydrogen cations formed from atoms on one or both sides of ethane. The D₂H⁺:D₃⁺ ratio can be modified by a factor of two or more using an adaptive feedback method.  In addition, two-dimensional scans of linear chirp and third-order dispersion are conducted for a few fourth-order dispersion values while the D₂H⁺ and D₃⁺ production are monitored.  In an effort to better understand the processes leading to D₃⁺ formation, we conduct COLTRIMS measurements of dissociative ionization of C₂D₆ to complement the velocity map imaging data obtained during the control experiments.