Low-temperature thermodynamic study of the metastable empty clathrate hydrates using molecular simulations
| Autor: | Saman Alavi, Fernando J. A. L. Cruz, José P. B. Mota |
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| Přispěvatelé: | LAQV@REQUIMTE, DQ - Departamento de Química |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
empty clathrate hydrates
Atmospheric Science Materials science Clathrate hydrate Thermodynamics 02 engineering and technology p- V- T data 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Empty clathrate hydrates molecular dynamics 0104 chemical sciences Molecular dynamics thermodynamics Temperature and pressure Geochemistry and Petrology Space and Planetary Science Metastability structure p−V−T data isobaric heat capacity 0210 nano-technology isobaric expansivity Bar (unit) |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| DOI: | 10.1021/acsearthspacechem.9b00009 |
| Popis: | POCI-01-0145-FEDER - 007265. RE-QUIMTE/BPD/004/2016. The thermodynamics of metastable empty sI-clathrate hydrates are probed over broad temperature and pressure ranges, 100 ≤ T (K) ≤ 220 and 1 ≤ p (bar) ≤ 5000, respectively, by large-scale simulations and compared with experimental data at 1 bar. The whole p-V-T surface obtained is fitted by the universal form of the Parsafar and Mason equation of state with an accuracy of 99.7-99.9%. Framework deformation brought about by the applied temperature follows a parabolic law, and there is a critical temperature above which the isobaric thermal expansion becomes negative, ranging from 194.7 K at 1 bar to 166.2 K at 5000 bar. That response to the applied (p, T) field is analyzed in terms of angle and distance descriptors of a classical tetrahedral structure and observed to occur essentially by means of angular alteration for (p, T) > (2000 bar, 200 K). The length of the hydrogen bonds responsible for framework integrity is insensitive to the thermodynamic conditions and its average value is r (O-H)=0.25 nm. authorsversion published |
| Databáze: | OpenAIRE |
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