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| Titel |
Estimating the NH₃:H₂SO₄ ratio of nucleating clusters in atmospheric conditions using quantum chemical methods |
| VerfasserIn |
T. Kurtén, L. Torpo, M. R. Sundberg, V.-M. Kerminen, H. Vehkamäki, M. Kulmala  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 10 ; Nr. 7, no. 10 (2007-05-25), S.2765-2773 |
| Datensatznummer |
250005001
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| Publikation (Nr.) |
 copernicus.org/acp-7-2765-2007.pdf |
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| Zusammenfassung |
| We study the ammonia addition reactions of H2SO4·NH3
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 NH3:H2SO4 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. |
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