Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods
Item
Title (Dublin Core)
Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods
Description (Dublin Core)
We study the ammonia addition reactions of H<sub>2</sub>SO<sub>4</sub>·NH<sub>3</sub> molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd order Møller-Plesset perturbation theory). Together with results from previous studies, we use the computed values to estimate an upper limit for the ammonia content of small atmospheric clusters, without having to explicitly include water molecules in the quantum chemical simulations. Our results indicate that the NH<sub>3</sub>:H<sub>2</sub>SO<sub>4</sub> mole ratio of small molecular clusters in typical atmospheric conditions is probably around 1:2. High ammonia concentrations or low temperatures may lead to the formation of ammonium bisulfate (1:1) clusters, but our results rule out the formation of ammonium sulfate clusters (2:1) anywhere in the atmosphere. A sensitivity analysis indicates that the qualitative conclusions of this study are not affected even by relatively large errors in the calculation of electronic energies or vibrational frequencies.
Creator (Dublin Core)
Kurtén, T.
Torpo, L.
Sundberg, M. R.
Kerminen, V.-M.
Vehkamäki, H.
Kulmala, M.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-7-2765-2007
https://acp.copernicus.org/articles/7/2765/2007/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
