Structure and vibrations of cerium in silica glass from molecular dynamics simulations

Abstract

Molecular dynamics simulations are performed to investigate the effect of cerium on the structural and vibrational properties of silica glass. At low-concentration levels, the cerium ions tend to generate longer bonds with bridging oxygens than nonbridging ones, the proportion of which is associated with the average bond length varied with cerium coordination. Formed in the presence of cerium, the bond angles exhibit strong dependence on the types of Ce-O bonds that bring about different angular distributions. Despite the discrepancy in the structures between Ce 3+ and Ce 4+ , similar characteristics of vibrations are observed for the two states. In comparison with the glass formers, the vibrations of cerium that contribute primarily to the low-frequency region show a less localized behavior, whereas the acoustic-like and optic-like modes separate at a much smaller frequency.

First-principles study of lithium aluminosilicate glass scintillators

“…The distribution reveals two main peaks at approximately 97° and 124° for the Si–O–Ce 3+ linkage. This distribution is similar to the one previously reported by Tian et al , 45 albeit with a less pronounced tail. The angles between 75° and 150° were considered to be Si–BO–Ce 3+ (BO denoting bridging oxygen), while the remaining tail was attributed to Si–NBO–Ce 3+ .…”

“…44 The partial RDF of Ce 3+ –O shows a main peak at 2.38 Å, in close agreement with previous simulations and experimental results. 44–46…”

“…Another feature of GSR2 glass is that there are more undercoordinated states (4 and 5) present in the glass network, whereas the over-coordinated states (8 and 9) appear to be more populated in glasses GS2 and GSR1. According to Tian et al 45 who studied cerium-doped silica glasses, Ce 3+ coordination distribution ranges from 3 to 8 in the simplest case of pure vitreous silica, with an average coordination number of 5.0. By comparing these values to the work of Du et al 46 on phospho-aluminosilicate glasses, Ce 3+ has a wider range and a higher coordination number from 5 to 8.…”

“…44 The partial RDF of Ce 3+ -O shows a main peak at 2.38 Å, in close agreement with previous simulations and experimental results. [44][45][46] To characterize the effect of R Al/M ratio on the bulk chemistry of the glass scintillator, the clustering behaviour of Ce 3+ in the glasses was analysed. Clustering and phase separation are the main limiting constraints of rare-earth element concentration in silicate glasses.…”

Improving structure and properties of lead phosphate glass through precipitation of few crystals from CeO2

“…Cerium oxide (CeO2) has been used in many types of materials that subjected to irradiation as a stabilizer or sensitizer agent. In order to improve irradiation resistance and luminescence properties, a small doping percentage has been added to certain types of glasses [10][11][12]. Glasses or glass ceramics that have a superior ability Egyptian Journal of Chemistry http://ejchem.journals.ekb.eg/ ________________________________________________ Egypt.…”