A three-dimensional Monte Carlo model for coarsening kinetics of the bi-continuous system via surface diffusion and its application to nanoporous gold

2020 ◽  
Vol 174 ◽  
pp. 33-38 ◽  
Author(s):  
Gaeun Son ◽  
Youngkyun Son ◽  
Hansol Jeon ◽  
Ju-Young Kim ◽  
Sukbin Lee
Keyword(s):  
Monte Carlo ◽  
Surface Diffusion ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Continuous System ◽  
Nanoporous Gold ◽  
Coarsening Kinetics ◽  
Kinetics Of

Monte Carlo modeling of production of three alpha-particles in low energy n +12C interactions

2021 ◽  
Vol 36 (25) ◽  
pp. 2150182
Author(s):  
Khusniddin K. Olimov ◽  
Vladimir V. Lugovoi ◽  
Kosim Olimov ◽  
Maratbek Shodmonov ◽  
Kadyr G. Gulamov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Alpha Particles ◽  
Incident Neutron ◽  
Excitation Energies ◽  
Collision Event ◽  
Direct Decay ◽  
Calculation Results

To describe [Formula: see text] interactions with production of three [Formula: see text]-particles at incident neutron kinetic energy of 14 MeV in a nuclear (photo) emulsion, a Monte Carlo model is proposed for four channels of decay of an excited carbon-12 nucleus into three [Formula: see text]-particles. The Monte Carlo calculation results describe well the experimental data on the distribution of the angle between the three-dimensional momenta of all pairs of [Formula: see text]-particles in a collision event, on the distribution of the angle between the projections of the momentum vectors of all pairs of [Formula: see text]-particles in collision event on each of the coordinate planes, on the distribution of the sum of the kinetic energies of all pairs of [Formula: see text]-particles in a collision event, and the distribution of projections of the momenta of [Formula: see text]-particles on the coordinate planes. The best agreement of the Monte Carlo model results with the experimental data is achieved if the direct decay [Formula: see text] and decay through the formation of an intermediate beryllium nucleus [Formula: see text] are generated with equal probabilities, while the excitation energies of 3.04 MeV, 1.04 MeV, and 0.1 MeV for the beryllium nucleus are generated with relative weights of 75%, 15%, and 10%, respectively.

scholarly journals A 3D particle Monte Carlo approach to studying nucleation

2017 ◽  
Author(s):  
Christoph Köhn ◽  
Martin Bødker Enghoff ◽  
Henrik Svensmark
Keyword(s):  
Monte Carlo ◽  
Sulphuric Acid ◽  
Nucleation Rate ◽  
Particle Density ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Initial Particle ◽  
Time Step ◽  
Size Dependent ◽  
Discrete Nature

Abstract. The nucleation of sulphuric acid molecules plays a key role in the formation of aerosols. We here present a three dimensional particle Monte Carlo model to study the growth of sulphuric acid clusters as well as its dependence on the ambient temperature and the initial particle density.We initiate a swarm of sulphuric acid molecules with a size of 0.15 nm with densities between 107 and 108 cm−3 at temperatures of 200 and 300 K. After every time step, we update the position and velocity of particles as a function of size-dependent diffusion coefficients. If two particles encounter, we merge them and add their volumes and masses. Inversely, we check after every time step whether a polymer evaporates liberating a molecule.We present the spatial distribution as well as the size distribution calculated from individual clusters. We also calculate the nucleation rate of clusters with a radius of 0.85 nm as a function of time, initial particle density and temperature. For 200 K, the nucleation rate increases as a function of time; for 300 K we observe an interplay between clustering and evaporation and thus the oscillation of the nucleation rate around the mean nucleation rate. The nucleation rates obtained from the presented model agree well with experimentally obtained values which serves as a benchmark of our code. In contrast to previous nucleation models, we here present for the first time a code capable of tracing individual particles and thus of capturing the physics related to the discrete nature of particles.

scholarly journals Self-learning kinetic Monte Carlo model for arbitrary surface orientations

2013 ◽  
Vol 1559 ◽  
Author(s):  
Andreas Latz ◽  
Lothar Brendel ◽  
Dietrich E. Wolf
Keyword(s):  
Monte Carlo ◽  
Specific Surface ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
The Self ◽  
Transition Rates ◽  
Local Orientation ◽  
Realistic Potential ◽  
Self Learning

ABSTRACTWhile the self-learning kinetic Monte Carlo (SLKMC) method enables the calculation of transition rates from a realistic potential, implementations of it were usually limited to one specific surface orientation. An example is the fcc (111) surface in Latz et al. 2012, J. Phys.: Condens. Matter 24, 485005. This work provides an extension by means of detecting the local orientation, and thus allows for the accurate simulation of arbitrarily shaped surfaces. We applied the model to the diffusion of Ag monolayer islands and voids on a Ag(111) and Ag(001) surface, as well as the relaxation of a three-dimensional spherical particle.

A hybrid continuum/kinetic Monte Carlo model for surface diffusion

2004 ◽  
Vol 365 (1-2) ◽  
pp. 66-72 ◽  
Author(s):  
S.P.A. Gill ◽  
P.E. Spencer ◽  
A.C.F. Cocks
Keyword(s):  
Monte Carlo ◽  
Surface Diffusion ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Model

A Three-Dimensional Monte Carlo Model for Phosphorus Implants into (100) Single-Crystal Silicon

1997 ◽  
Vol 490 ◽  
Author(s):  
Myung-Sik Son ◽  
Ho-Jung Hwang
Keyword(s):  
Monte Carlo ◽  
Single Crystal ◽  
Room Temperature ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Single Crystal Silicon ◽  
Amorphous Region ◽  
Electronic Energy ◽  
Crystal Silicon ◽  
Dynamic Simulation Model

ABSTRACTAn alternative three-dimensional (3D) Monte Carlo (MC) dynamic simulation model for phosphorus implant into (100) single-crystal silicon has been developed which incorporates the effects of channeling and damage. This model calculates the trajectories of both implanted ions and recoiled silicons and concurrently and explicitly affects both ions and recoils due to the presence of accumulative damage. In addition, the model for room-temperature implant accounts for the self-annealing effect using our defined recombination probabilities for vacancies and interstitials saved on the unit volumes. Our model has been verified by the comparison with the previously published SIMS data over commonly used energy range between 10 and 180 keV, using our proposed empirical electronic energy loss model. The 3D formations of the amorphous region and the ultra-shallow junction around the implanted region could be predicted by using our model, TRICSI (TRansport Ions into Crystal-Silicon).

Phase Field Simulation of Coarsening Kinetics in Al-Sc and Al-Sc-Zr Alloys

2008 ◽  
Vol 1128 ◽  
Author(s):  
H. Zapolsky ◽  
J. Boisse ◽  
R. Patte ◽  
N. Lecoq
Keyword(s):  
Phase Field ◽  
Diffusion Coefficients ◽  
Three Dimensional ◽  
Ternary Alloys ◽  
Simulation Results ◽  
Coarsening Kinetics ◽  
Two Phases ◽  
Kinetics Of ◽  
Good Agreement ◽  
Zr Alloys

AbstractThe coarsening kinetics of γ’ precipitates in binary and ternary Al3Sc1-xZrx alloys is studied by using the two- and three-dimensional phase-field simulations. Our focus is on the influence of diffusion coefficients of Sc and Zr atoms on the transformation path kinetics from disordered f.c.c. matrix to two phases equilibrium state with γ’ precipitates and f.c.c. disordered matrix. Our simulation results demonstrate that in the case of binary alloys taking into account the concentration dependence of the mobility of atoms decreases the coarsening rate. In the case of ternary alloys we show that the Al3Sc particles precipitate first following by appearance of a Zr-rich shell. Our simulations results are in good agreement with experimental observations.

Computational Cost and Accuracy in Calculating Three-Dimensional Radiative Transfer: Results for New Implementations of Monte Carlo and SHDOM

2009 ◽  
Vol 66 (10) ◽  
pp. 3131-3146 ◽  
Author(s):  
Robert Pincus ◽  
K. Franklin Evans
Keyword(s):  
Monte Carlo ◽  
Radiative Transfer ◽  
Variance Reduction ◽  
Parallel Implementation ◽  
Monte Carlo Model ◽  
Computational Cost ◽  
Three Dimensional ◽  
Computation Time ◽  
Flux Divergence ◽  
Pixel Intensity

Abstract This paper examines the tradeoffs between computational cost and accuracy for two new state-of-the-art codes for computing three-dimensional radiative transfer: a community Monte Carlo model and a parallel implementation of the Spherical Harmonics Discrete Ordinate Method (SHDOM). Both codes are described and algorithmic choices are elaborated. Two prototype problems are considered: a domain filled with stratocumulus clouds and another containing scattered shallow cumulus, absorbing aerosols, and molecular scatterers. Calculations are performed for a range of resolutions and the relationships between accuracy and computational cost, measured by memory use and time to solution, are compared. Monte Carlo accuracy depends primarily on the number of trajectories used in the integration. Monte Carlo estimates of intensity are computationally expensive and may be subject to large sampling noise from highly peaked phase functions. This noise can be decreased using a range of variance reduction techniques, but these techniques can compromise the excellent agreement between the true error and estimates obtained from unbiased calculations. SHDOM accuracy is controlled by both spatial and angular resolution; different output fields are sensitive to different aspects of this resolution, so the optimum accuracy parameters depend on which quantities are desired as well as on the characteristics of the problem being solved. The accuracy of SHDOM must be assessed through convergence tests and all results from unconverged solutions may be biased. SHDOM is more efficient (i.e., has lower error for a given computational cost) than Monte Carlo when computing pixel-by-pixel upwelling fluxes in the cumulus scene, whereas Monte Carlo is more efficient in computing flux divergence and downwelling flux in the stratocumulus scene, especially at higher accuracies. The two models are comparable for downwelling flux and flux divergence in cumulus and upwelling flux in stratocumulus. SHDOM is substantially more efficient when computing pixel-by-pixel intensity in multiple directions; the models are comparable when computing domain-average intensities. In some cases memory use, rather than computation time, may limit the resolution of SHDOM calculations.

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