Molecular mechanism of the clathrate cage formation in structure-II cyclopentane hydrate: An ab initio study

Wen, Jing; Zhang, Yongsheng; Zhou, Wanru; Fu, Yuanyuan; Zhao, Weilong; Wei, Sheng

doi:10.1016/j.jct.2020.106063

Cited by 4 publications

(2 citation statements)

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“…The results of these thermodynamic analyses are similar to the results by Walsh et al Later, they discovered that the simultaneous formation of the coplanar bicages is not thermodynamically feasible, that is, cages are more likely to appear one by one, and the formation of cages has an autocatalytic effect . Recently, Wen et al studied the formation mechanism of the 5 12 6 4 cage in the process of sII CP hydrate nucleation and also obtained similar conclusions . In the past decade, our group has studied CH 4 @(H 2 O) n ( n = 16, 18, 20, 22, 24) clusters with standard and nonstandard water cages that may appear in the process of hydrate nucleation.…”

Section: Introductionsupporting

confidence: 82%

“…29 Recently, Wen et al studied the formation mechanism of the 5 12 6 4 cage in the process of sII CP hydrate nucleation and also obtained similar conclusions. 30 In the past decade, our group has studied CH 4 @(H 2 O) n (n = 16,18,20,22,24) clusters with standard and nonstandard water cages that may appear in the process of hydrate nucleation. We found that a small-sized monocage could grow into a largesized monocage via the "dimer-insertion" mechanism, and plenty of standard 5 12 cages and nonstandard 4 1 5 10 6 2 cages exist at the initial stage of hydrate nucleation.…”

Section: Introductionmentioning

confidence: 99%

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Stability and NMR Chemical Shift of Amorphous Precursors of Methane Hydrate: Insights from Dispersion-Corrected Density Functional Theory Calculations Combined with Machine Learning

Wang

Tang

et al. 2020

J. Phys. Chem. B

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Clathrate hydrates of natural gases are important backup energy sources. It is thus of great significance to explore the nucleation process of hydrates. Hydrate clusters are building blocks of crystalline hydrates and represent the initial stage of hydrate nucleation. Using dispersion-corrected density functional theory (DFT-D) combined with machine learning, herein, we systematically investigate the evolution of stabilities and nuclear magnetic resonance (NMR) chemical shifts of amorphous precursors from monocage clusters CH4(H2O) n (n = 16–24) to decacage clusters (CH4)10(H2O) n (n = 121–125). Compared with planelike configurations, the close-packed structures formed by the water-cage clusters are energetically favorable. The 512 cages are dominant, and the emerging amorphous precursors may be part of sII hydrates at the initial stage of nucleation. Based on our data set, the possible initial fusion pathways for water-cage clusters are proposed. In addition, the 13C NMR chemical shifts for encapsulated methane molecules also showed regular changes during the fusion of water-cage clusters. Machine learning can reproduce the DFT-D results well, providing a structure–energy-property landscape that could be used to predict the energy and NMR chemical shifts of such multicages with more water molecules. These theoretical results present vital insights into the hydrate nucleation from a unique perspective.

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Section: Introductionsupporting

confidence: 82%