A transferable coarse-grained model for hydrogen-bonding liquids.
We present here a recent development of a generalized coarse-grained model for use in molecular simulations. In this model, interactions between coarse-grained particles consist of both van der Waals and explicit electrostatic components. As a result, the coarse-grained model offers the transferability that is lacked by most current effective-potential based approaches. The previous center-of-mass framework (P. A. Golubkov and P. Ren, J. Chem. Phys., 2006, 125, 64103) is generalized here to include arbitrary off-center interaction sites for both Gay-Berne and multipoles. The new model has been applied to molecular dynamic simulations of neat methanol liquid. By placing a single point multipole at the oxygen atom rather than at the center of mass of methanol, there is a significant improvement in the ability to capture hydrogen-bonding. The critical issue of transferability of the coarse-grained model is verified on methanol-water mixtures, using parameters derived from neat liquids without any modification. The mixture density and internal energy from coarse-grained molecular dynamics simulations show good agreement with experimental measurements, on a par with what has been obtained from more detailed atomic models. By mapping the dynamics trajectory from the coarse-grained simulation into the all-atom counterpart, we are able to investigate atomic-level structure and interaction. Atomic radial distribution functions of neat methanol, neat water and mixtures compare favorably to experimental measurements. Furthermore, hydrogen-bonded 6- and 7-molecule chains of water and methanol observed in the mixture are in agreement with previous atomic simulations.
Golubkov
Pavel A
PA
Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA.
Wu
Johnny C
JC
Ren
Pengyu
P
D003198:Computer Simulation; D004058:Diffusion; D006860:Hydrogen Bonding; D000432:Methanol / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D055672:Static Electricity; D014867:Water / Q000737:chemistry
D014867:Water; D000432:Methanol