Uptake of N<sub>2</sub>O<sub>5</sub> by aqueous aerosol unveiled using chemically accurate many-body potentials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35273144.
- Also identified by DOI 10.1038/s41467-022-28697-8 and PMC identifier 8913772.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The reactive uptake of N<sub>2</sub>O<sub>5</sub> to aqueous aerosol is a major loss channel for nitrogen oxides in the troposphere. Despite its importance, a quantitative picture of the uptake mechanism is missing. Here we use molecular dynamics simulations with a data-driven many-body model of coupled-cluster accuracy to quantify thermodynamics and kinetics of solvation and adsorption of N<sub>2</sub>O<sub>5</sub> in water. The free energy profile highlights that N<sub>2</sub>O<sub>5</sub> is selectively adsorbed to the liquid-vapor interface and weakly solvated. Accommodation into bulk water occurs slowly, competing with evaporation upon adsorption from gas phase. Leveraging the quantitative accuracy of the model, we parameterize and solve a reaction-diffusion equation to determine hydrolysis rates consistent with experimental observations. We find a short reaction-diffusion length, indicating that the uptake is dominated by interfacial features. The parameters deduced here, including solubility, accommodation coefficient, and hydrolysis rate, afford a foundation for which to consider the reactive loss of N<sub>2</sub>O<sub>5</sub> in more complex solutions.