Activation of Specific Reagents in Molecular Films by Sub-Ionization Electrons: Chlorobenzene/Water Films.

Control over chemical reactivity remains a fundamental challenge in synthesis chemistry, where targeting a specific reactant represents the ultimate goal. While photoactivation is a well-established approach for selective excitation, electron-induced chemistry offers a complementary pathway with high efficacy. In this study, we investigate the effects of low-energy electron irradiation on prototypical chlorobenzene/water molecular films, demonstrating that chlorobenzene can be selectively dissociated via a resonant process occurring at ~1 eV. At higher electron energies (>6 eV), multiple reaction pathways become accessible, including the fragmentation of both water and chlorobenzene molecules. Our study provides a perspective strategy for achieving reagent-specific control in complex molecular assemblies via low-energy electrons, offering new insights into electron-driven surface chemistry and reaction dynamics at the molecular level.