UV-induced modification of fused silica: Insights from ReaxFF-based molecular dynamics simulations

Tian, Ye; Du, Jincheng; Zu, Xiaotao; Han, Wei; Yuan, Xiaodong; Zheng, Wanguo

doi:10.1063/1.4963204

Cited by 13 publications

(4 citation statements)

References 23 publications

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“…The Si–O–Si angle peaks at 145° in the ZSM-5 catalyst model and reaches a maximum value of 148° in the hydrated ZSM-5 catalyst model, and these data are in good accordance with previous work on computational techniques and molecular models for ab initio calculations of solid silicates by Teppen et al In the hydrated Al/ZSM-5 catalyst model, the Si–O–Si angle peaks at 155°. The O–Si–O angle centers at 109–110° in three systems and is in good agreement with the 110° of the O–Si–O angle in the ReaxFF molecular simulation of hyperthermal silicon oxidation by Khalilov et al and ReaxFF molecular dynamic simulation of the structure of silica by Chowdhury et al The Si–O–H angle reaches a maximum proportion at 124° in hydrated ZSM-5 and 117° in the hydrated Al/ZSM-5 model, which is very close to the result 121° of Si–O–H in the molecular dynamics research of silanols by Kobayashi et al The geometry information obtained in this work could also be validated by other similar previous works. − …”

Section: Resultssupporting

confidence: 83%

Molecular Simulation of the Catalytic Cracking of Hexadecane on ZSM-5 Catalysts Based on Reactive Force Field (ReaxFF)

Chen

Zhao

et al. 2017

Energy Fuels

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Fluid catalytic cracking (FCC) is one of the most dominant processes for heavy feedstock conversion. By using ReaxFF dynamic simulations, the catalytic pyrolysis of hexadecane was investigated with the presence of ZSM-5, hydrated ZSM-5, and hydrated Al/ZSM-5 catalysts under high temperatures. Multimolecular simulation results showed that the hydrated ZSM-5 catalyst has good catalytic reactivity at higher temperatures, and the surface hydroxyl group could promote the yield of ethylene. The hydrated Al/ZSM-5 catalyst was more suitable for the production of small molecules under lower temperatures, and the introduction of aluminum would increase the yield of C3∼C4 and prevent the formation of C–O bonds. The unimolecular simulations confirmed that the introduction of aluminum in the hydrated Al/ZSM-5 catalyst would be beneficial to the dehydrogenation of reactant molecules. Thermal stability simulations of catalysts revealed that the introduction of aluminum into the ZSM-5 catalyst could stabilize the Si–O structure and inhibit the formation of a C–O bond.

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Section: Resultssupporting

confidence: 83%

Molecular Simulation of the Catalytic Cracking of Hexadecane on ZSM-5 Catalysts Based on Reactive Force Field (ReaxFF)

Chen

Zhao

et al. 2017

Energy Fuels

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“…The 2‐ and 3‐member rings resulted from dividing 6‐member rings into smaller rings by 5 Si, which is consistent with the observations in the coordination number in Figure and ring statistics in Figure . The 2‐ and 3‐member rings give rise to the side peak in the Si–O–Si and the Si–Si–Si BAD in Figure . Increase in the population of 5 Si with increasing pressure in silica or silicate glasses was observed in several experiment and simulation studies .…”

Section: Discussionmentioning

confidence: 82%

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

2019

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Silica, sharing the same tetrahedral order and many structural, thermodynamic and dynamic anomalies with water, has been speculated to have a density increase upon melting similar to water. In this work, an increase in density upon melting cristobalite silica and a shallow density maximum followed by a density minimum during cooling of silica liquid are observed in classical molecular dynamics simulations. The density maximum gradually diminishes with the increase in alkali size/content in alkali silicate glasses. The structural origin of the anomalous density maximum in silica is revealed by detailed structural analysis. During the cooling process, a range of rings with different sizes form in liquid silica, with 6-member rings being the most dominant, which cause the silica network to open up and compensate the regular volume shrinkage upon cooling. These two competing factors lead to a density maximum, but to a less extent than that observed in melting of cristobalite silica. With the increase in modifier size/content in the alkali silicate glasses, the connectivity of silica network gradually breaks down; the population of 6-member rings decrease with the increase in smaller or larger rings, therefore the density maximum becomes less obvious and eventually disappears. K E Y W O R D Satomistic simulation, density maximum, silica, silicates

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“…In details, the PDF of irradiated quartz shows (1) broader peaks and (2) an additional peak centered around 2Å. While (1) suggests an overall higher degree of disorder in the network, (2) arises from the presence of coordination defects [35]. Indeed, as detailed in Ref.…”

Section: A Irradiation-induced Damagementioning

confidence: 85%

Irradiation-induced topological transition in SiO2: Structural signature of networks' rigidity

Wang

Krishnan

et al. 2017

Journal of Non-Crystalline Solids

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By affecting the connectivity of atomic networks, composition, temperature, or pressure can induce topological transitions between the three atomic states of rigidity-flexible, isostatic, and stressed-rigid. However, no clear structural signature of such transitions has been elucidated thus far. Here, based on realistic molecular dynamics simulations of irradiation-induced damage in quartz, we report the first evidence of a rigid-to-flexible rigidity transition controlled by structural variations only. This topological transition is shown to arise from the simultaneous loss of atomic eigenstress and onset of network flexibility, and features a well-defined structural signature in the medium-range order of the atomic network.

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UV-induced modification of fused silica: Insights from ReaxFF-based molecular dynamics simulations

Cited by 13 publications

References 23 publications

Molecular Simulation of the Catalytic Cracking of Hexadecane on ZSM-5 Catalysts Based on Reactive Force Field (ReaxFF)

Molecular Simulation of the Catalytic Cracking of Hexadecane on ZSM-5 Catalysts Based on Reactive Force Field (ReaxFF)

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

Irradiation-induced topological transition in SiO2: Structural signature of networks' rigidity

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