Vibrational Quantum-State-Controlled Reactivity in the O 2 + + C 3 H 4 Reaction

Quantum-state-controlled reactivity is a long-standing goal in the field of physical chemistry. In this work, we explore the vibrational-state-dependent behavior of the ion-molecule reaction between O2+ in distinct vibrational states and two isomers of C3H4, allene (H2C3H2) and propyne (H3C3H). While most products are formed regardless of the vibrational state of O2+, the branching ratios are influenced by vibrational excitation, and a new product, C2O+, appears exclusively in the excited-state reactions. This selective formation of C2O+ demonstrates that vibrational excitation can effectively activate a reaction pathway, providing direct evidence of quantum-state control in the reactivity. These results represent an important step toward the goal of quantum-state-controlled chemistry in molecular systems.