| Autor: |
Waller SE; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Yang Y; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Castracane E; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Racow EE; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Kreinbihl JJ; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Nickson KA; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States., Johnson CJ; Department of Chemistry , Stony Brook University , 100 Nicolls Road , Stony Brook , New York 11794 , United States. |
| Abstrakt: |
Acid-base cluster chemistry drives atmospheric new particle formation (NPF), but the details of the growth mechanisms are difficult to experimentally probe. Clusters of ammonia, alkylamines, and sulfuric acid, species fundamental to NPF, are probed by infrared spectroscopy. These spectra show that substitution of amines for ammonia, which is linked to accelerated growth, induces profound structural rearrangement in clusters with initial compositions (NH 4 + ) n+1 (HSO 4 - ) n (1 ≤ n ≤ 3). This rearrangement is driven by the loss of N-H hydrogen bond donors, yielding direct bisulfate-bisulfate hydrogen bonds, and its onset with respect to cluster composition indicates that more substituted amines induce rearrangement at smaller sizes. A simple model counting hydrogen bond donors and acceptors explains these observations. The presence of direct hydrogen bonds between formal anions shows that hydrogen bonding can compete with Coulombic forces in determining cluster structure. These results suggest that NPF mechanisms may be highly dependent on amine identity. |
