An atmospherically relevant acid: HNO3

Here we briefly review our theoretical work on nitric acid dissociation at an aqueous interface, an issue important in a wide range of atmospheric contexts, employing both quantum chemical methods and Car-Parrinello molecular dynamics simulations. A first aspect concerns whether or not this dissociation, via proton transfer to a neighboring water molecule, occurs as a function of the acid’s location atop and at various depths below the surface. Further aspects concern the molecular level details of the mechanism, i.e. which motions are important, of the first proton transfer to form a contact ion pair, and of the subsequent proton transfer to produce a solvent-separated ion pair from that contact ion pair.