Molecular Dynamics Simulation of Transport and Structural Properties of CO2 Using Different Molecular Models

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• 作者：Haimin Zhong ; Shuhui Lai ; Jinyang Wang ; Wenda Qiu ; Hans-Dietrich L眉demann ; Liuping Chen
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2015
• 出版时间：August 13, 2015
• 年：2015
• 卷：60
• 期：8
• 页码：2188-2196
• 全文大小：640K
• ISSN：1520-5134

文摘

The diffusion coefficients (D_s), viscosities (畏), and structural properties of carbon dioxide (CO₂) have been studied using molecular dynamics (MD) simulation. Three fully flexible models (MSM-flex, EPM2-flex, and TraPPE-flex) from the literature are used to model CO₂. Present simulations have extended the temperature range from 223 K to 450 K and pressures up to 200 MPa for the first time. Generally, the simulation results show a good agreement with the experimental ones. The overall satisfaction of the EPM2-flex model is found to be the best, with an average absolute relative deviation of 6.83 % for D_s and of 2.87 % for 畏, respectively. However, the TraPPE-flex model performs best at low temperatures below 273 K. Meanwhile, the lifetime of CO₂ molecules in the first solvation shell (蟿^s) is calculated, and the qualitative correlation between 蟿^s and D_s as well as 蟿^s and 畏 is discussed. Finally, the structures of CO₂ fluid in different thermodynamic states are investigated by calculating radial distribution functions and using a clustering algorithm.