Under these experimental conditions, the observed dynamics has to occur where the probe laser induces the reactions resulting in further ionization [30]. The two-step decay model [26] was applied to explain the above-mentioned fragmentation of DCPD to CPD, shown in Figure 8a. The fitting of the rise and decay components of the transients were done by Matlab® programming using the curve fitting Levenberg–Marquardt algorithm. The best fit decay constants for the biexponential decay components of C10H12+ ion signal is τ1=35fs and τ2=240fs, while that for C5H6+ ion signal is τ1=36fs and τ2=280fs, respectively. These decay constants conform to the previously reported time constants of norbornene and norbornadiene [22,23]. The transients of the reaction fragment C5H6+ are sufficiently different from that of the parent ion C10H12+ indicating that we are studying the distinct dynamics of the neutrals and not that of the parent ion fragmentation [24]. Applying laser control principles under such experimental circumstances also confirms that we are controlling the product yield of C5H6+, resulting from the photochemical reaction of DCPD.
