A theoretical study of temperature dependence of cluster formation from sulfuric acid and ammonia

2014 ◽  
Vol 433 ◽  
pp. 60-66 ◽  
Author(s):  
Nara Lee Chon ◽  
Shan-Hu Lee ◽  
Hai Lin
Keyword(s):  
Sulfuric Acid ◽  
Temperature Dependence ◽  
Theoretical Study ◽  
Cluster Formation

Theoretical study of temperature dependence and Rayleigh scattering properties of chloride hydration clusters

2014 ◽  
Vol 16 (36) ◽  
pp. 19241 ◽  
Author(s):  
Shuai Jiang ◽  
Teng Huang ◽  
Yi-Rong Liu ◽  
Kang-Ming Xu ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Rayleigh Scattering ◽  
Theoretical Study

scholarly journals Chemical ionization of clusters formed from sulfuric acid and dimethylamine or diamines

2016 ◽  
Author(s):  
Coty N. Jen ◽  
Jun Zhao ◽  
Peter H. McMurry ◽  
David R. Hanson
Keyword(s):  
Sulfuric Acid ◽  
Chemical Ionization ◽  
Flow Reactor ◽  
Cluster Formation ◽  
Mass Spectrometers ◽  
Model Calculations ◽  
Molecule Reaction ◽  
Base Content ◽  
Atmospheric Nucleation ◽  
High Base

Abstract. Chemical ionization (CI) mass spectrometers are used to study atmospheric nucleation by detecting clusters produced by reactions of sulfuric acid and various basic gases. These instruments typically use nitrate to deprotonate and thus chemically ionize the clusters. In this study, we compare cluster concentrations measured using either nitrate or acetate. Clusters were formed in a flow reactor from vapors of sulfuric acid and dimethylamine, ethylene diamine, tetramethylethylene diamine, or butanediamine (also known as putrescine). These comparisons show that nitrate is unable to chemically ionize clusters with high base content. In addition, we vary the ion-molecule reaction time to probe ion processes which include proton-transfer, ion-molecule clustering, and decomposition of ions. Ion decomposition upon deprotonation by acetate/nitrate was observed. More studies are needed to quantify to what extent ion decomposition affects observed cluster content and concentrations, especially those chemically ionized with acetate since it deprotonates more types of clusters than nitrate. Model calculations of the neutral and ion cluster formation pathways are also presented to better identify the cluster types that are not efficiently deprotonated by nitrate. Comparison of model and measured clusters indicate that sulfuric acid dimer with two diamines and sulfuric acid trimer with two or more base molecules are not efficiently chemical ionized by nitrate. We conclude that acetate CI provides better information on cluster abundancies and their base content than nitrate CI.

scholarly journals A Monte Carlo approach for determining cluster evaporation rates from concentration measurements

2016 ◽  
Author(s):  
Oona Kupiainen-Määttä
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Markov Chain ◽  
Sulfuric Acid ◽  
Markov Chain Monte Carlo ◽  
Mass Spectrometer ◽  
Large Fraction ◽  
Cluster Formation ◽  
Unknown Parameters ◽  
Ammonia Clusters

Abstract. Evaporation rates of small negatively charged sulfuric acid–ammonia clusters are determined by combining detailed cluster formation simulations with cluster distributions measured at CLOUD. 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 HSO4− and HSO4− ⋅ H2SO4 signals may result from fragmentation of larger clusters, most importantly the HSO4− ⋅ (H2SO4)2 trimer.

Theoretical study on reaction mechanism of sulfuric acid and ammonia and hydration of (NH4)2SO4

2012 ◽  
Vol 131 (2) ◽  
Author(s):  
Wei-Wei Liu ◽  
Xiao-Lin Wang ◽  
Shi-Lu Chen ◽  
Yun-Hong Zhang ◽  
Ze-Sheng Li
Keyword(s):  
Sulfuric Acid ◽  
Reaction Mechanism ◽  
Theoretical Study
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