Direct observation on H-elimination enhancement from C₂H₄ through non-adiabatic process by femtosecond laser induced Coulomb explosion

Abstract Ethylene, the simplest model of a carbon-carbon double bond system, is pivotal in numerous chemical and biological processes. By employing intense infrared (IR) laser pump-probe techniques alongside coincidence measurements, we investigated the ultrafast non-adiabatic dynamics involved in the breakage of carbon-carbon double bonds and hydrogen elimination in ethylene's dissociation. Our study entailed analyzing the dynamic Kinetic Energy Release (KER) spectra to assess three bond-breaking scenarios, the movements of nuclei, and the structural changes around the carbon atoms. This allowed us to evaluate the relaxation dynamics and characteristics of various dissociative states. Notably, we observed a significant rise in the yield of fragments resulting from CH bond breakage as the delay time extended, suggesting non-adiabatic coupling through conical intersections from CC bond breakage as a probable cause.