Homogenous nucleation rate of CO2 hydrates using transition interface sampling

2021 ◽  
Vol 154 (16) ◽  
pp. 164507
Author(s):  
A. Arjun ◽  
Peter G. Bolhuis
Keyword(s):  
Nucleation Rate ◽  
Homogenous Nucleation ◽  
Transition Interface

Homogenous nucleation rate measurements of n-butanol using UCPC (TSI model 3025)

1995 ◽  
Vol 26 ◽  
pp. S769-S770
Author(s):  
Jarkko Augustin ◽  
Kaarle Hämeri ◽  
Markku Kulmala ◽  
Evgenii Krissinel'
Keyword(s):  
Nucleation Rate ◽  
Homogenous Nucleation

scholarly journals On the roles of sulphuric acid and low-volatility organic vapours in the initial steps of atmospheric new particle formation

2010 ◽  
Vol 10 (22) ◽  
pp. 11223-11242 ◽  
Author(s):  
P. Paasonen ◽  
T. Nieminen ◽  
E. Asmi ◽  
H. E. Manninen ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Nucleation Rate ◽  
Formation Rate ◽  
Particle Formation ◽  
New Particle Formation ◽  
Relative Contribution ◽  
Homogenous Nucleation ◽  
Order Of Magnitude ◽  
Sulphuric Acid Concentration

Abstract. Sulphuric acid and organic vapours have been identified as the key components in the ubiquitous secondary new particle formation in the atmosphere. In order to assess their relative contribution and spatial variability, we analysed altogether 36 new particle formation events observed at four European measurement sites during EUCAARI campaigns in 2007–2009. We tested models of several different nucleation mechanisms coupling the formation rate of neutral particles (J) with the concentration of sulphuric acid ([H2SO4]) or low-volatility organic vapours ([org]) condensing on sub-4 nm particles, or with a combination of both concentrations. Furthermore, we determined the related nucleation coefficients connecting the neutral nucleation rate J with the vapour concentrations in each mechanism. The main goal of the study was to identify the mechanism of new particle formation and subsequent growth that minimizes the difference between the modelled and measured nucleation rates. At three out of four measurement sites – Hyytiälä (Finland), Melpitz (Germany) and San Pietro Capofiume (Italy) – the nucleation rate was closely connected to squared sulphuric acid concentration, whereas in Hohenpeissenberg (Germany) the low-volatility organic vapours were observed to be dominant. However, the nucleation rate at the sulphuric acid dominant sites could not be described with sulphuric acid concentration and a single value of the nucleation coefficient, as K in J=K [H2SO4]2, but the median coefficients for different sites varied over an order of magnitude. This inter-site variation was substantially smaller when the heteromolecular homogenous nucleation between H2SO4 and organic vapours was assumed to take place in addition to homogenous nucleation of H2SO4 alone, i.e., J=KSA1[H2SO4]2+KSA2[H2SO4][org]. By adding in this equation a term describing homomolecular organic vapour nucleation, Ks3[org]2, equally good results were achieved. In general, our results suggest that organic vapours do play a role, not only in the condensational growth of the particles, but also in the nucleation process, with a site-specific degree.

scholarly journals On the roles of sulphuric acid and low-volatility organic vapours in the initial steps of atmospheric new particle formation

2010 ◽  
Vol 10 (5) ◽  
pp. 11795-11850 ◽  
Author(s):  
P. Paasonen ◽  
T. Nieminen ◽  
E. Asmi ◽  
H. E. Manninen ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Nucleation Rate ◽  
Formation Rate ◽  
Particle Formation ◽  
New Particle Formation ◽  
Relative Contribution ◽  
Homogenous Nucleation ◽  
Condensational Growth ◽  
Sulphuric Acid Concentration

Abstract. Sulphuric acid and organic vapours have been identified as the key components in the ubiquitous secondary new particle formation in the atmosphere. In order to assess their relative contribution and spatial variability, we analyzed altogether 36 new particle formation events observed at four European measurement sites during EUCAARI campaigns in 2007–2009. We tested models of several different nucleation mechanisms coupling the formation rate of neutral particles (J) with the concentration of sulphuric acid ([H2SO4]) or low-volatility organic vapours ([org]) condensing on sub-4 nm particles, or with a combination of both concentrations. Furthermore, we determined the related nucleation coefficients connecting the neutral nucleation rate J with the vapour concentrations in each mechanism. The main goal of the study was to identify the mechanism of new particle formation and subsequent growth that minimizes the difference between the modeled and measured nucleation rates. At three out of four measurement sites – Hyytiälä (Finland), Melpitz (Germany) and San Pietro Capofiume (Italy) – the nucleation rate was closely connected to squared sulphuric acid concentration, whereas in Hohenpeissenberg (Germany) the low-volatility organic vapours were observed to be dominant. However, the nucleation rate at the sulphuric acid dominant sites could not be described with sulphuric acid concentration and a single value of the nucleation coefficient, as K in J=K [H2SO4]2, but the coefficients seemed to vary between the sites. This inter-site variation was substantially smaller when the heteromolecular homogenous nucleation between H2SO4 and organic vapours was assumed to take place in addition to homogenous nucleation of H2SO4 alone, i.e. J=KSA1 [H2SO4]2+KSA2 [H2SO4][org]. By adding in this equation a term describing homomolecular organic vapour nucleation, Ks3 [org]2, equally good results were achieved. In general, our results suggest that organic vapours do play a role, not only in the condensational growth of the particles, but as well in the nucleation process, with a site specific degree.

Rare event simulation

2017 ◽  
Author(s):  
Michael P. Allen ◽  
Dominic J. Tildesley
Keyword(s):  
Rare Event ◽  
Path Sampling ◽  
Rapid Progress ◽  
Computationally Efficient ◽  
Transition Path ◽  
Transition Path Sampling ◽  
Event Simulation ◽  
Reaction Coordinates ◽  
Simulation Techniques ◽  
Transition Interface

The development of techniques to simulate infrequent events has been an area of rapid progress in recent years. In this chapter, we shall discuss some of the simulation techniques developed to study the dynamics of rare events. A basic summary of the statistical mechanics of barrier crossing is followed by a discussion of approaches based on the identification of reaction coordinates, and those which seek to avoid prior assumptions about the transition path. The demanding technique of transition path sampling is introduced and forward flux sampling and transition interface sampling are considered as rigorous but computationally efficient approaches.

scholarly journals Low-temperature nucleation anomaly in silicate glasses shown to be artifact in a 5BaO·8SiO2 glass

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xinsheng Xia ◽  
D. C. Van Hoesen ◽  
Matthew E. McKenzie ◽  
Randall E. Youngman ◽  
K. F. Kelton
Keyword(s):  
Nucleation Rate ◽  
Experimental Approach ◽  
Cluster Formation ◽  
Heating Time ◽  
Silicate Glasses ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Real Phenomenon ◽  
Satisfactory Answer ◽  
Over 40 Years

AbstractFor over 40 years, measurements of the nucleation rates in a large number of silicate glasses have indicated a breakdown in the Classical Nucleation Theory at temperatures below that of the peak nucleation rate. The data show that instead of steadily decreasing with decreasing temperature, the work of critical cluster formation enters a plateau and even starts to increase. Many explanations have been offered to explain this anomaly, but none have provided a satisfactory answer. We present an experimental approach to demonstrate explicitly for the example of a 5BaO ∙ 8SiO2 glass that the anomaly is not a real phenomenon, but instead an artifact arising from an insufficient heating time at low temperatures. Heating times much longer than previously used at a temperature 50 K below the peak nucleation rate temperature give results that are consistent with the predictions of the Classical Nucleation Theory. These results raise the question of whether the claimed anomaly is also an artifact in other glasses.

Analysis of water–ethanol nucleation rate data with two component nucleation theorems

2000 ◽  
Vol 113 (8) ◽  
pp. 3261-3269 ◽  
Author(s):  
Hanna Vehkamäki ◽  
Ian J. Ford
Keyword(s):  
Nucleation Rate ◽  
Rate Data ◽  
Two Component

Direct measurement of activation time and nucleation rate in capillary-condensed water nanomeniscus

2013 ◽  
Vol 103 (21) ◽  
pp. 213107 ◽  
Author(s):  
Baekman Sung ◽  
Jongwoo Kim ◽  
Corey Stambaugh ◽  
Sung-Jin Chang ◽  
Wonho Jhe
Keyword(s):  
Direct Measurement ◽  
Nucleation Rate ◽  
Activation Time ◽  
Condensed Water

scholarly journals Study of Nucleation and Growth in the Organometallic Synthesis of Magnetic Alloy Nanocrystals: The Role of Nucleation Rate in Size Control of CoPt3 Nanocrystals.

ChemInform ◽  
2003 ◽  
Vol 34 (42) ◽  
Author(s):  
Elena V. Shevchenko ◽  
Dmitri V. Talapin ◽  
Heimo Schnablegger ◽  
Andreas Kornowski ◽  
Oerjan Festin ◽  
...  
Keyword(s):  
Nucleation Rate ◽  
Size Control ◽  
Nucleation And Growth ◽  
Magnetic Alloy ◽  
Organometallic Synthesis ◽  
Alloy Nanocrystals
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