CHCl·- activates oxygen-containing gases: Uncovering intrinsic reaction nature from a multiscale theoretical investigation.

Understanding the ionic reactivity of CHCl˙- anions is essential for modeling chemical processes in interstellar media, plasmas, and planetary atmospheres. Using multiscale computational simulations, this work examines the adsorption and reaction behaviors of eight oxygen-containing gases (O2, CO, CO2, NO, N2O, NO2, COS, SO2) on CHCl˙- clusters. Our findings reveal that electrostatic interactions dominate system stabilization over dispersion forces. The O2 environment strongly induces activation of the CHCl˙- anion, while COS exhibits minimal reactivity. Bond activation occurs across O-O, C-O, C-S, N-O, N-N, and S-O linkages, with binding strengths following O2 > NO2 > SO2 > CO. Although CO2, NO, and N2O interactions are thermodynamically limited at room temperature, they become accessible upon heating. These results demonstrate that anion-molecule reactivity emerges from coupled mass transport, electrostatic compatibility, and bond lability, thereby advancing predictive frameworks for radical-mediated chemistry.