Open AccessMolecular dynamics study of small helium cluster diffusion in titanium
Author(s) -
Min Chen
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.126602
Subject(s) - molecular dynamics , diffusion , cluster (spacecraft) , materials science , chemical physics , atom (system on chip) , lattice diffusion coefficient , embedded atom model , helium , thermodynamics , statistical physics , effective diffusion coefficient , physics , atomic physics , computational chemistry , chemistry , embedded system , programming language , medicine , radiology , computer science , magnetic resonance imaging
The diffusions of He atom and small He clusters in Ti at different temperatures are simulated by molecular dynamics. The prefactors and the activation energies of diffusion coefficients are calculated. It can be concluded that the diffusion is anisotropic. Simulations show that prefactors of diffusion coefficients are different from those of He species diffusing in different directions, but the activation energies are the same. The result demonstrates that it is insufficient to predict the diffusion behavior of He in metal when only the energy barrier in static lattice is considered. Dynamics calculations are necessary to obtain the correct prefactors. Another counterintuitive observation is that He-dimer migrates more quickly than single He atom does at room temperature. The results emphasize the importance of dynamics simulations in predicting diffusion behavior of He in metals.