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Title: Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A 2O–2MO–4SiO 2 with molecular dynamics simulations

Abstract

A series of mixed cation silicate glasses of the composition A2O – 2MO – 4SiO2, with A=Li,Na,K and M=Ca,Sr,Ba has been investigated by means of molecular dynamics simulations in order to understand the effect of the nature of the cations on the mobility of the alkaline-earth ions within the glass network. The size of the alkaline-earth cation was found to affect the inter-atomic distances, the coordination number distributions and the bond angle distributions , whereas the medium-range order was almost unaffected by the type of the cation. All the alkaline-earth cations contribute to lower vibrational frequencies but it is observed that that there is a shift to smaller frequencies and the vibrational density of states distribution gets narrower as the size of the alkaline-earth increases. The results from our modeling for the ionic diffusion of the alkaline-earth cations are in a qualitative agreement with the experimental observations in that there is a distinct correlation between the activation energy for diffusion of alkaline earth-ions and the cation radii ratio. An asymmetrical linear behavior in the diffusion activation energy with increasing size difference is observed. The results can be described on the basis of a theoretical model that relates the diffusion activationmore » energy to the electrostatic interactions of the cations with the oxygens and the elastic deformation of the silicate network.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1242345
Report Number(s):
PNNL-SA-110319
Journal ID: ISSN 0022-3093
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Non-Crystalline Solids
Additional Journal Information:
Journal Volume: 422; Journal ID: ISSN 0022-3093
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
glass; molecular dynamics; alkaline-earth; structure; diffusion

Citation Formats

Konstantinou, Konstantinos, Sushko, Petr, and Duffy, Dorothy M. Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A2O–2MO–4SiO2 with molecular dynamics simulations. United States: N. p., 2015. Web. doi:10.1016/j.jnoncrysol.2015.05.005.
Konstantinou, Konstantinos, Sushko, Petr, & Duffy, Dorothy M. Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A2O–2MO–4SiO2 with molecular dynamics simulations. United States. doi:10.1016/j.jnoncrysol.2015.05.005.
Konstantinou, Konstantinos, Sushko, Petr, and Duffy, Dorothy M. Fri . "Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A2O–2MO–4SiO2 with molecular dynamics simulations". United States. doi:10.1016/j.jnoncrysol.2015.05.005.
@article{osti_1242345,
title = {Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A2O–2MO–4SiO2 with molecular dynamics simulations},
author = {Konstantinou, Konstantinos and Sushko, Petr and Duffy, Dorothy M.},
abstractNote = {A series of mixed cation silicate glasses of the composition A2O – 2MO – 4SiO2, with A=Li,Na,K and M=Ca,Sr,Ba has been investigated by means of molecular dynamics simulations in order to understand the effect of the nature of the cations on the mobility of the alkaline-earth ions within the glass network. The size of the alkaline-earth cation was found to affect the inter-atomic distances, the coordination number distributions and the bond angle distributions , whereas the medium-range order was almost unaffected by the type of the cation. All the alkaline-earth cations contribute to lower vibrational frequencies but it is observed that that there is a shift to smaller frequencies and the vibrational density of states distribution gets narrower as the size of the alkaline-earth increases. The results from our modeling for the ionic diffusion of the alkaline-earth cations are in a qualitative agreement with the experimental observations in that there is a distinct correlation between the activation energy for diffusion of alkaline earth-ions and the cation radii ratio. An asymmetrical linear behavior in the diffusion activation energy with increasing size difference is observed. The results can be described on the basis of a theoretical model that relates the diffusion activation energy to the electrostatic interactions of the cations with the oxygens and the elastic deformation of the silicate network.},
doi = {10.1016/j.jnoncrysol.2015.05.005},
journal = {Journal of Non-Crystalline Solids},
issn = {0022-3093},
number = ,
volume = 422,
place = {United States},
year = {2015},
month = {5}
}