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 HCO2H on the reaction between OH• and HCl. Potential energy profiles indicate that both NH3 and HCO2H 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 HCO2H catalyzed channels prefer a single hydrogen atom transfer path. Besides, both NH3 and HCO2H catalyzed paths have higher rate constant values as compared to that of the water catalyzed path.