Structural Origins of RF₃/NaRF₄ Nanocrystal Precipitation from Phase-Separated SiO₂–Al₂O₃–RF₃–NaF Glasses: A Molecular Dynamics Simulation Study

Abstract

Oxyfluoride glass-ceramics with RF3 or NaRF4 (R3+: rare earth elements) nanocrystals are considered as favorable hosts for luminescence applications. In this work, we utilized large-scale molecular dynamics (MD) simulations with effective partial charge potentials to study a series of oxyfluoride glasses that are of interest to the precipitation of RF3 or NaRF4 nanocrystals as previous experiment results suggested. The results show that phase separation exists in all glass compositions with fluoride-rich regions made up of R3+, Na+, and F– and oxide-rich regions consisting of aluminosilicate networks. These fluoride-enriched regions can serve as the precursor for RF3, cubic and hexagonal NaRF4, and NaF crystal precipitation. The results also confirm that the concentration of Na+ in the fluoride phase plays a key role in determining the crystal phases (RF3, NaRF4, or NaF) and crystal structure (cubic vs hexagonal NaRF4) to be precipitated. Consequently, this study shows that MD simulations with effective potentials can fill the gap in the structural understanding of oxyfluoride glass and provide insights into atomic scale information of the phase separation behavior that is useful in predicting the potential crystal types in oxyfluoride glass. When coupled with experimental validations, these simulations can expedite the exploration of novel luminescent oxyfluoride glass ceramics.

Understanding the binding affinity of noscapines with protease of SARS-CoV-2 for COVID-19 using MD simulations at different temperatures

“…However, the designed molecules were filtered against the protease of SARS-CoV-2 for COVID-19 based on total energy or binding energy (kcal/mol) of drug-target complex using iGEMDOCK Singh et al, 2019;Zhao et al, 2019). Authors, used iGEMDOCK to understand the binding of noscapine and its derivatives with the target to find hit candidation.…”

“…Authors, used iGEMDOCK to understand the binding of noscapine and its derivatives with the target to find hit candidation. The absorption (% ABS) was calculated using the Equation (1) proposed by Zhao et al (2019).…”

Structural Origins of BaF2/Ba1 −xRxF2 +x/RF3 Nanocrystals Formation from Phase Separated Fluoroaluminosilicate Glass: A Molecular Dynamic Simulation Study

“…[19,20] Our previous results suggested that www.advancedsciencenews.com www.advtheorysimul.com the fluoride phase separation is a result of the immiscibility nature between the oxide and fluoride network. [21,22] Furthermore, fluoride crystals precipitate from the separated fluoride phase region under certain conditions, [23][24][25][26] meaning that the fluoride crystals have similar composition with the fluoride phase. Therefore, understanding the fluoride phase separation in oxyfluoride glass can not only help to explore the structure-property relationship between the amorphous glass structure and luminescence centers but can also help to predict the possible crystals to be precipitated and to design glass-ceramics with better luminescent properties.…”

“…[34] MD simulations with effective pair-wise partial-charge potential have been applied successfully in studying mixed anion glass as well and the results can be compared with the corresponding experiments. [22] Here, in order to understand structural origins of M 1 − x R x F 2 + [22] Here, in order to understand structural origins of M 1 − x R x F 2 +…”

“…In oxyfluoride glass, fluoride phase separation can be observed over certain composition ranges with electron microscopes, small‐angle scattering technique, or thermoanalytical techniques . Our previous results suggested that the fluoride phase separation is a result of the immiscibility nature between the oxide and fluoride network . Furthermore, fluoride crystals precipitate from the separated fluoride phase region under certain conditions, meaning that the fluoride crystals have similar composition with the fluoride phase.…”