A Monte Carlo approach for determining cluster evaporation rates from concentration measurements
Evaporation rates of small negatively charged sulfuric acid–ammonia clusters are determined by combining detailed cluster formation simulations with cluster distributions measured in the CLOUD experiment at CERN. The analysis is performed by varying the evaporation rates with Markov chain Monte C...
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/14585/2016/acp-16-14585-2016.pdf |
| Summary: | Evaporation rates of small negatively charged sulfuric
acid–ammonia clusters are determined by combining detailed cluster formation
simulations with cluster distributions measured in the CLOUD experiment at CERN. The analysis is
performed by varying the evaporation rates with Markov chain Monte Carlo
(MCMC), running cluster formation simulations with each new set of
evaporation rates and comparing the obtained cluster distributions to the
measurements. In a second set of simulations, the fragmentation of clusters
in the mass spectrometer due to energetic collisions is studied by treating
also the fragmentation probabilities as unknown parameters and varying them
with MCMC. This second set of simulations results in a better fit to the
experimental data, suggesting that a large fraction of the observed
HSO<sub>4</sub><sup>−</sup> and HSO<sub>4</sub><sup>−</sup> ⋅ H<sub>2</sub>SO<sub>4</sub> signals may result
from fragmentation of larger clusters, most importantly the
HSO<sub>4</sub><sup>−</sup> ⋅ (H<sub>2</sub>SO<sub>4</sub>)<sub>2</sub> trimer. |
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| ISSN: | 1680-7316 1680-7324 |