Tracking molecular isomerization process with high harmonic generation by ultra-short laser pulses

By analyzing the HHG spectra emitted from HCN molecule while interacting with ultra-short laser pulses during the chemical reaction path of the HCN/HNC isomerization, we identify the intensity peaks nearby the stable, meta-stable and transition states. We also obtain similar results for the acetylene/vinylidene isomerization, indicating that the existence of the HHG intensity peaks at the stable states of molecules may be a universal effect. This finding may be useful as a tool for tracking the molecular isomerization process.