Two-dimensional simulation of nanocluster formation and comparison with experiments

Ohkubo, Takeru; Kuwata, Masahiro; Luk’yanchuk, Boris; Yabe, Takashi

doi:10.1117/12.482083

Cited by 3 publications

(3 citation statements)

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“…The considered examples reveal that even the corrected use of this rate may lead to unpredictable deviations from the correct solution. It is not surprising, therefore, that the predicted by the CNT-rate methodology distribution of Silicon clusters in laser ablation significantly deviates from the experimental distributions [22]. The proposed methodology of coupling between the CNT rate equations and the one-dimensional isentropic gas expansion equations, though very approximate, can be used to test the applicability of either the traditional or the modified scheme in each practical case.…”

Section: Discussionmentioning

confidence: 99%

Applicability of the Homogeneous Nucleation Theory to the Condensation in Free Gas Expansions

Zeifman

Zhong

Levin

2005

AIP Conference Proceedings

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Abstract. The traditional application of the classical homogeneous nucleation theory (CNT) to the condensation in rapidly expanding flows involves the use of the steady-state nucleation rate. Since this rate is derived under the assumption of both steady-state and isobaric/isothermal conditions, the applicability of CNT to highly nonequilibrium environments may be questionable. In addition, the usual strategy of CNT -gas dynamics coupling violates the original nucleation theory even in the isothermal/isobaric environment. In this study, we consider condensation in jets freely expanding into a vacuum. Using the isentropic solution, we approximate the time-dependent pressure and temperature in a given small volume of a gas that is moving along the jet axis with the flow velocity. Several possible strategies of CNT implementation are considered within this volume. It is shown that the terminal cluster distributions are strongly affected by the steady-state assumption and that the original CNT rate equations should be integrated into a computational scheme to model the coupled condensation flow.

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Section: Discussionmentioning

confidence: 99%

Applicability of the Homogeneous Nucleation Theory to the Condensation in Free Gas Expansions

Zeifman

Zhong

Levin

2005

AIP Conference Proceedings

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“…Two extreme cases of either very low or relatively high background pressure are considered in most theoretical studies of laser plume expansion. The plume expansion into vacuum can be described as self-similar adiabatic one with condensation phenomenon [36,37,38,39,40,41].]. In the case of high background pressure, shock waves were shown to be produced during the plume expansion into background gases [42].…”

Section: Introductionmentioning

confidence: 99%

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

2014

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International audienceLaser ablation (LA) is a unique tool for nanoparticle synthesis. The main advantages of this method are in its green character and in the possibility of a control over particle size. In this study, we examine nanoparticle formation by laser ablation under different experimental conditions and analyse the results based on the developed models. The dynamics of the laser plume expansion is examined revealing the role of the background pressure and laser pulse parameters. As a result, the ablated material is compressed and a part of it becomes supersaturated. The so-called "primary" nanoparticles are formed at this stage. Then, nanoparticle aggregation/fragmentation enters into play leading to the formation of the secondary particles. In addition, laser- assisted fragmentation of nanoparticles is also examined. Based on numerical modeling we shed light on the above mechanisms by using different numerical approaches, such as molecular dynamics, Monte Carlo, numerical hydrodynamics, and analytical analysis. Calculations are performed for metallic targets under different background conditions. The obtained results explain recent experimental findings and help to predict the role of the experimental parameters. The performed analysis thus indicates ways of a control over nanoparticle synthesis © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

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“…The presence of nanoparticles in the laser plume is then explained by using a Zel'dovich-Raizer condensation model (Zeldovich, 1966;Luk'yanchuk et al, 1998;Gusarov et al, 2000). This approach is appropriate for interpretation of the experimental findings obtained in laser ablation with hundred of nanoseconds and longer laser pulses, and in the presence of a background gas (Ohkubo et al, 2003;Boldarev et al, 2001). In the PLA with shorter laser pulses, however, clusters can be ejected directly from the target as a result of the target disintegration by laser-induced explosion-like process (Bulgakov, 2004;Amoruso et al, 2004;Zhigilei, 2003).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Nanoparticle Formation by Laser Ablation

Itina¹

2010

Laser Pulse Phenomena and Applications

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Two-dimensional simulation of nanocluster formation and comparison with experiments

Cited by 3 publications

References 0 publications

Applicability of the Homogeneous Nucleation Theory to the Condensation in Free Gas Expansions

Applicability of the Homogeneous Nucleation Theory to the Condensation in Free Gas Expansions

Laser-based synthesis of nanoparticles: role of laser parameters and background conditions

Mechanisms of Nanoparticle Formation by Laser Ablation

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