Manipulating intracluster ion-molecule reactions in the ethylene dimer via femtosecond-laser intensity

Manipulating intracluster ion-molecule reactions via the control of vibrational excitation states of the parent cluster ion holds significant promise. Herein, we studied the effect of vibrational excitation on intracluster ionmolecule reactions within the ethylene dimer ion (C₂H₄)₂⁺ focusing on the formation of C₄H₈⁺, C₃H₅⁺, and C₄H₇⁺ ions, utilizing femtosecond laser pulses and ab initio calculations. Via coincident photoelectron and ion detection, we reconstructed the initial vibrational excitation state population (IVP) of the parent ion and found a correlation between the IVP and product formation. Our study shows that the branching ratios for C₄H₈⁺, C₄H₇⁺, and C₃H₅⁺ ions are dominated by low, medium, and high vibrational states, respectively, and there is a clear competition among them. Further analysis confirmed that laser intensity affects the IVP, which determines the yield of each decay channel. Our study establishes a direct link between IVP and product distribution in intracluster ion-molecule reactions and demonstrates the potential to steer reaction outcomes by varying laser field intensity, which opens avenues to the tailored control of reactions in various intracluster systems.