Accommodation coefficients for water vapor at the air/water interface

Vieceli, John; Roeselová, Martina; Tobias, Douglas J.

doi:10.1016/j.cplett.2004.06.038

Cited by 56 publications

(70 citation statements)

References 26 publications

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“…Furthermore, the apparent sustained coherence of an organic film when water condensation occurs, and the rapid response in droplet size through condensation, suggests that the growth of a droplet preserves islands of organic surfactants and opens up areas of uncoated water surface on which water condensation can occur rapidly. Molecular-dynamic simulations for droplets coated in a long-chain fatty acid could provide further insights into the dynamics that are occurring (11,28,37). Finally, although it is not possible to determine the lowest possible limit on the evaporation coefficient, with the value declining up to n = 18 chain length, the influence of longer-chain surfactants will provide greater insight into the mechanism of interfacial transport.…”

Section: Resultsmentioning

confidence: 99%

Influence of organic films on the evaporation and condensation of water in aerosol

Davies

Miles

Haddrell

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

135

167

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Uncertainties in quantifying the kinetics of evaporation and condensation of water from atmospheric aerosol are a significant contributor to the uncertainty in predicting cloud droplet number and the indirect effect of aerosols on climate. The influence of aerosol particle surface composition, particularly the impact of surface active organic films, on the condensation and evaporation coefficients remains ambiguous. Here, we report measurements of the influence of organic films on the evaporation and condensation of water from aerosol particles. Significant reductions in the evaporation coefficient are shown to result when condensed films are formed by monolayers of long-chain alcohols [C n H (2n+1) OH], with the value decreasing from 2.4 × 10 −3 to 1.7 × 10 −5 as n increases from 12 to 17. Temperature-dependent measurements confirm that a condensed film of long-range order must be formed to suppress the evaporation coefficient below 0.05. The condensation of water on a droplet coated in a condensed film is shown to be fast, with strong coherence of the long-chain alcohol molecules leading to islanding as the water droplet grows, opening up broad areas of uncoated surface on which water can condense rapidly. We conclude that multicomponent composition of organic films on the surface of atmospheric aerosol particles is likely to preclude the formation of condensed films and that the kinetics of water condensation during the activation of aerosol to form cloud droplets is likely to remain rapid.water transport | organic monolayers | mass accommodation | surface films T he transport of volatile and semivolatile components between the condensed and gas phases in aerosol during evaporation or condensation is important for understanding cloud microphysics, atmospheric chemistry, the delivery of drugs to the lungs, and the applications of aerosols in materials and combustion science. For example, the uptake of chemical species to atmospheric aerosol particles facilitates chemical reactions (1), the condensation of water on cloud condensation nuclei allows cloud droplets to form (2), the uptake of water on pharmaceutical aerosol can affect their deposition pattern within the lungs (3), and the evaporation rates of solvents in spray drying processes influence the structure and morphology of the final microparticle (4). The rate of mass transport to or from an aerosol particle can be considered to involve the interplay of three mechanistic steps: gas phase diffusion, interfacial transfer, and bulk condensed phase diffusion. Different limiting regimes can be identified under which the rate of evaporation or condensation is determined by any one of these steps (5).The Knudsen number is the ratio of the mean free path of gas phase molecules to the particle radius. At low Knudsen number, in the limits of large particle size and high gas pressure, gas phase diffusion usually determines evaporation and condensation rates. Bulk phase diffusion is limiting when the viscosity of the particle impedes transport to or from the surfac...

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Section: Resultsmentioning

confidence: 99%

Influence of organic films on the evaporation and condensation of water in aerosol

Davies

Miles

Haddrell

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

135

167

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“…-The interface is rough on molecular length scales (e.g., ∼1 nm) and fluctuates on time scales of ∼10 −12 s -Molecular events at the interface (e.g., exchange of water molecules on the surface with those below the surface) occur on time scales of 10 −12 s -The condensation and evaporation of water to and from the surface is equivalent to about 1 event per molecular area every 10 −8 s, and therefore do not play a significant role in the shorter time molecular events at the interface -Calculated values of the surface tension of water for a variety of water models for many of the more commonly used potentials yield values that are within about 30% of experiment (Lee and Scott, 1980;Wilson et al, 1987b;Matsumoto and Kataoka, 1988;Zhu et al, 1991;Lie et al, 1993;Matsumoto et al, 1993;Alejandre et al, 1995;Dang and Chang, 1997;Taylor et al, 1996;Paul and Chandra, 2003;Vieceli et al, 2004).…”

Section: Molecular Dynamics Simulationsmentioning

confidence: 99%

“…The condensation of water on aqueous droplets is a special case of molecular uptake, but for molecular simulations, which treat all molecules as distinguishable, the methods used are the same as for other molecular species. Water adsorption has been studied extensively by molecular simulations (Nagayama and Tsuruta, 2003;Dang and Garrett, 2004;Morita et al, 2004a;Vacha et al, 2004;Vieceli et al, 2004). In an interesting recent study, a theoretical model of liquid water evaporation was presented based on transition state theory (TST) (Smith et al, 2006;Cappa et al, 2007).…”

Section: Molecular Dynamics Simulationsmentioning

confidence: 99%

“…Calculations have also been performed to study the initial sticking, or surface accommodation, of the collisions of several molecules with water surfaces (Wilson and Pohorille, 1997;Nagayama and Tsuruta, 2003;Morita, 2003;Roeselova et al, 2004;Tsuruta and Nagayama, 2004;Vieceli et al, 2004;Morita et al, 2004a, b;Vieceli et al, 2005). The conclusion from these studies is that for collisions of hydrophilic molecules near room temperature nearly all molecules initially stick to the surface.…”

Section: Molecular Dynamics Simulationsmentioning

confidence: 99%

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An overview of current issues in the uptake of atmospheric trace gases by aerosols and clouds

et al. 2010

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Abstract.A workshop was held in the framework of the ACCENT (Atmospheric Composition Change -a European Network) Joint Research Programme on "Aerosols" and the Programme on "Access to Laboratory Data". The aim of the workshop was to hold "Gordon Conference" type discussion covering accommodation and reactive uptake of water vapour and trace pollutant gases on condensed phase atmospheric materials. The scope was to review and define the current state of knowledge of accommodation coefficients for water vapour on water droplet and ice surfaces, and uptake of trace gas species on a variety of different surfaces characteristic of the atmospheric condensed phase particulate matter and cloud droplets. Twenty-six scientists participated in this Correspondence to: C. E. Kolb (kolb@aerodyne.com) meeting through presentations, discussions and the development of a consensus review.In this review we present an analysis of the state of knowledge on the thermal and mass accommodation coefficient for water vapour on aqueous droplets and ice and a survey of current state-of the-art of reactive uptake of trace gases on a range of liquid and solid atmospheric droplets and particles. The review recommends consistent definitions of the various parameters that are needed for quantitative representation of the range of gas/condensed surface kinetic processes important for the atmosphere and identifies topics that require additional research.

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“…Musolino and Trout, using the finite temperature string method, find a theoretical value of α = 0.25 7 while Vieceli et al find a value of α = 0.99 using direct molecular dynamics (MD) simulations with a polarizable force field. 10 Varilly and Chandler report a value of α ≈ 1 from a transition path sampling investigation finding the evaporation process to be consistent with diffusion out of a deep potential well without additional barrier.…”

Section: Introductionmentioning

confidence: 99%

Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory

Schlesinger

Sellberg

Nilsson

et al. 2016

The Journal of Chemical Physics

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In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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Accommodation coefficients for water vapor at the air/water interface

Cited by 56 publications

References 26 publications

Influence of organic films on the evaporation and condensation of water in aerosol

Influence of organic films on the evaporation and condensation of water in aerosol

An overview of current issues in the uptake of atmospheric trace gases by aerosols and clouds

Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory

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