ISSN:
1572-9567
Keywords:
densified silica
;
fast multipole method
;
fracture
;
high pressure
;
intermediate range order
;
kinetic roughening
;
molecular dynamics
;
multiresolution algorithms
;
parallel computing
;
porous silica
;
structural transformations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A highly efficient multiresolution algorithm has been developed to carry out large-scale molecular dynamics (MD) simulations for systems with long-range Coulomb and three-body covalent interactions. The algorithm combines the reduced cell and fast multipole methods and multiple time-step approach. Pressure-induced structural transformation, loss of intermediate range order, and dynamcal correlations in SiO2, glass are investigated with the moleculardynamics method. At twice the normal density, the Si-O bond length increases, the Si O coordination changes from 4 to 6, and the O-Si-O band-angle changes from 109 to 90°. This is a tetrahedral-to-octahedral transformation, which was reported by Meade, Hemley, and Mao. Results for phonon density of states also reveal significant changes at high pressures. The multiresolution MD approach has been used to investigate the structural properties and mechanical failure in microporous silica. Structural correlations are characterized by the fractal dimension, internal surface area, and pore surface-tovolume ratio. Critical behavior at fracture is analyzed in terms of pore percolation, and kinetic roughening of fractured surface is also investigated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01448219
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