Homogeneous and heterogeneous nucleation of water vapor: A comparison using molecular dynamics simulation

Sepehri, Asghar; Amjad‐Iranagh, Sepideh; Golzar, Karim; Modarress, Hamid

doi:10.1016/j.chemphys.2013.07.005

Cited by 14 publications

(4 citation statements)

References 42 publications

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“…As shown in this figure, when we focus on a short time interval of the MSD plot, three characteristic patterns can be observed based on the media in which diffusion occurs. The initial stage in the MSD plot corresponds to a subdiffusive regime, where a nonlinear relationship to time can be seen. − The first part is followed by a typical diffusion process, in which the MSD increases linearly with time and the motion is Fickian. After normal diffusion, the local relaxation − and hopping regions are observed.…”

Section: Resultsmentioning

confidence: 99%

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Taghdisian¹,

Tasharrofi²,

Firoozjaie³

et al. 2019

J. Chem. Eng. Data

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In the present study, the effects of loading, topology, and extraframework ions on SO 2 diffusion in zeolites 13X and 5A were investigated using molecular dynamics simulation. The study was performed at different loadings, that is, 4, 8, 16, and 32 molecules per unit cell (UC) and various temperatures, that is, 300, 400, 500, and 600 K. The simulation results showed that in the same SO 2 loading and temperature, the self-diffusion coefficients in zeolite 13X are higher than those of 5A, which can be attributed to the smaller pore window size along with strong electrostatic forces of Ca cations in 5A. This result is in accordance with higher mean square displacements (MSDs) of SO 2 molecules in zeolite 13X, in which more hopping can be observed between cages. A closer inspection of the MSD plots in a short time interval (e.g., 200 ps) demonstrates a stepwise behavior which is an important aspect of topology effects, where the hopping between cages and relaxation within cages take place. In both types of zeolites, the self-diffusion coefficient of SO 2 molecules initially displays a slight increase at low loading and follows a slow decrease at high loading of SO 2 . Such a loading-dependent behavior can be attributed to various interactions between SO 2 −SO 2 and SO 2 −zeolites/cations. With increasing the loading from 4 to 16 molecules/UC, although the SO 2 −SO 2 interaction increases, interaction between SO 2 molecules and zeolites (or cations) decreases, which leads to less restriction on diffusing SO 2 molecules. However, increasing the loading from 16 to 32 molecules/UC eventually increases the collision frequency among gas molecules, which is unfavorable to the diffusion process, and therefore, self-diffusion decreases.

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Section: Resultsmentioning

confidence: 99%

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Taghdisian¹,

Tasharrofi²,

Firoozjaie³

et al. 2019

J. Chem. Eng. Data

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“…The earliest data included here are by Miller et al 20 Nucleation rates in water vapour in argon ranging from 7.9 Â 10 7 to 2.9 Â 10 11 m À3 s À1 were measured for temperatures from 231. 41 Static diffusion chamber data. Brus et al 28,29 measured nucleation rates for water vapour in helium for temperatures from 290.00 to 320.00 K and nucleation rates from 4.5 Â 10 5 to 3.6 Â 10 8 m À3 s À1 .…”

Section: Survey Of Experimental Datamentioning

confidence: 99%

“…The supersaturation was then evaluated as a ratio of vapour density to the saturation vapour density. Sepehri et al 41 performed SPC/E simulations using the Nose´-Hoover thermostat. Zhang et al 42 simulated 10,000 SPC/E molecules using the Nose´-Hoover thermostat.…”

Section: Survey Of Molecular Simulation Datamentioning

confidence: 99%

Nucleation rates of droplets in supersaturated steam and water vapour–carrier gas mixtures between 200 and 450 K

Hrubý

Duška

Němec

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part A:

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We compare experimental nucleation rates for water vapour in various carrier gases, estimated nucleation rates for steam, and nucleation rates obtained from molecular simulations. The data for steam are deduced from empirical adjustments of the classical nucleation theory developed by various authors to reproduce pressure and optical data for condensing steam flows in converging-diverging nozzles and turbine stages. By combining the data for nucleation in carrier gases and the data for steam nucleation, an unprecedented temperature range of 250 K is available to study the temperature dependence of nucleation rate. Original results of molecular dynamic simulations for TIP4P/2005 force field in the NVE (system constrained by number of particles, volume and energy) conditions are provided. Correction of classical nucleation theory for non-isothermal nucleation conditions is applied to experimental and simulated data. The nucleation rate data for steam follow a similar temperature trend as the nucleation rate data for water vapour in carrier gases at lower temperatures. The ratio of observed nucleation rates to classical nucleation theory predictions decreases more steeply with temperature than the empirical correlation by Wö lk et al. (J Chem Phys 2002; 117: 4954-4960). On the contrary to experimental data, the ratios of nucleation rates computed from molecular simulations to classical nucleation theory predictions do not show a significant temperature trend.

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“…In addition, there has been recent investigations of the phase transitions of protonated Ar clusters using classical MD simulations [19]. Moreover, there has been a large focus on the nucleation of clusters composed of molecules commonly found in atmospheres, including the growth of water/ice clusters [20][21][22][23], and the study of the structure of aerosol nanoparticles [24]. In the past there also has been some theoretical analyses of small Ar n H + and Lennard-Jones (LJ) clusters.…”

Section: Introductionmentioning

confidence: 99%

Inner Energy Relaxation and Growth of Nano-Size Particles

Bredice¹,

Rozman²,

Smucker³

et al. 2023

Preprint

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In this study, molecular dynamics simulations were conducted to investigate the relaxation of the internal energy in nano-sized particles and its impact on the nucleation of atomic clusters. Quantummechanical potentials were utilized to analyze the growth and collision relaxation of the internal energy of ArnH + clusters in a metastable Ar gas. The results revealed that small nano-clusters are formed in highly excited rotational-vibrational states, and the relaxation of internal energy and growth of these nascent clusters are concurrent processes with a strong mutual influence. Under nonequilibrium growth conditions, the relaxation of internal energy can delay the cluster growth process. The rates of cluster growth and internal energy relaxation were found to be influenced by energytransfer collisions between cluster particles and free Ar atoms of the bath gas. Furthermore, the non-equilibrium growth and internal energy relaxation of small nano-clusters were found to depend on the structure of the cluster's atomic shells. An ensemble of molecular dynamics simulations were conducted to investigate the growth, time-evolution of kinetic and total energies of ArnH + clusters with specified n ≤ 11, and the results were explained by collisional relaxation processes described by the Boltzmann equation. Finally, the general relationship between the rates of internal energy relaxation and non-equilibrium growth of nano-particles is discussed.

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Homogeneous and heterogeneous nucleation of water vapor: A comparison using molecular dynamics simulation

Cited by 14 publications

References 42 publications

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Nucleation rates of droplets in supersaturated steam and water vapour–carrier gas mixtures between 200 and 450 K

Inner Energy Relaxation and Growth of Nano-Size Particles

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Homogeneous and heterogeneous nucleation of water vapor: A comparison using molecular dynamics simulation

Cited by 14 publications

References 42 publications

Loading-Dependent Diffusion of SO2 in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Loading-Dependent Diffusion of SO2 in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Nucleation rates of droplets in supersaturated steam and water vapour–carrier gas mixtures between 200 and 450 K

Inner Energy Relaxation and Growth of Nano-Size Particles

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Product

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Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology

Loading-Dependent Diffusion of SO₂ in 13X and 5A Using Molecular Dynamics: Effects of Extraframework Ions and Topology