Developing atomistic glass models using potential-free Monte Carlo method: From simple to complex structures
Singh, Shakti 1Chandra, Sharat1
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作者信息
1. HBNI
折叠
Abstract
We propose here a method to generate random networked amorphous structure using only readily available short-range properties like bond lengths, bond angles and connectivity of the constituents. This method is a variant of Monte-Carlo (MC) method wherein the basic constituents of an amorphous network i.e. rigid polyhedral units are connected randomly obeying certain steric constraints. The algorithm is designed to reproduce the medium-range order universally observed in glasses. The method resembles the reverse MC (RMC) method where a random move of an atom inside a box is accepted or rejected depending upon whether it decreases or increases the deviation from the experimentally observed features. However unlike RMC, this method does not demand large experimental sets of scattering data which are difficult to obtain for glasses. It rather relies on the stochasticity of MC method to produce glassy structures. The method presented here examines the possibility of developing glassy structures without employing either the computationally demanding melt-quench simulation or the information demanding RMC method. The algorithm is first validated against SiO2 glass structure by comparing with the available structures from other methods and experimental data. The method is then extended for developing more complex Iron Phosphate Glass (IPG) structures and a comparative study of the generated models is done with existing models of IPG developed using melt-quench scheme in classical Molecular Dynamics (MD). Through this study we conclude that the IPG model developed using MC method and subsequently equilibrated using MD agrees in all structural aspects with the model of IPG generated using melt-quench simulation, projecting the current recipe as an interesting alternative to melt-quench simulation for developing glass models.
Key words
Atomistic structure/Glass modelling/Random-network structures/Monte Carlo method/Iron Phosphate Glass model/Structural characterization in glass/IRON-PHOSPHATE-GLASSES/MOLECULAR-DYNAMICS SIMULATIONS/BOND-ANGLE DISTRIBUTION/SHARP DIFFRACTION PEAK/AMORPHOUS SIO2/NEUTRON-SCATTERING/SILICATE-GLASSES/NETWORKS/ORDER
NSTL
Elsevier