Effect of Ammonia and Formic Acid on the OH • + HCl Reaction in the Troposphere: Competition between Single and Double Hydrogen Atom Transfer Pathways.

Quantum chemical calculations at QCISD and CCSD(T) levels of theory have been performed to investigate the effect of NH3 and HCO2 H on the reaction between OH• and HCl. Potential energy profiles indicate that both NH3 and HCO2 H catalyzed reactions could proceed through two different channels, namely, single and double hydrogen atom transfer. Theoretically calculated rate constants for both the catalysts show that both NH3 and HCO2 H catalyzed channels prefer a single hydrogen atom transfer path. Besides, both NH3 and HCO2 H catalyzed paths have higher rate constant values as compared to that of the water catalyzed path.