PMID- 24628149
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20141121
LR  - 20140317
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 140
IP  - 10
DP  - 2014 Mar 14
TI  - Multi-scale coarse-graining of non-conservative interactions in molecular 
      liquids.
PG  - 104104
LID - 10.1063/1.4866142 [doi]
AB  - A new bottom-up procedure for constructing non-conservative (dissipative and 
      stochastic) interactions for dissipative particle dynamics (DPD) models is 
      described and applied to perform hierarchical coarse-graining of a polar 
      molecular liquid (nitromethane). The distant-dependent radial and shear frictions 
      in functional-free form are derived consistently with a chosen form for 
      conservative interactions by matching two-body force-velocity and three-body 
      velocity-velocity correlations along the microscopic trajectories of the 
      centroids of Voronoi cells (clusters), which represent the dissipative particles 
      within the DPD description. The Voronoi tessellation is achieved by application 
      of the K-means clustering algorithm at regular time intervals. Consistently with 
      a notion of many-body DPD, the conservative interactions are determined through 
      the multi-scale coarse-graining (MS-CG) method, which naturally implements a 
      pairwise decomposition of the microscopic free energy. A hierarchy of MS-CG/DPD 
      models starting with one molecule per Voronoi cell and up to 64 molecules per 
      cell is derived. The radial contribution to the friction appears to be dominant 
      for all models. As the Voronoi cell sizes increase, the dissipative forces 
      rapidly become confined to the first coordination shell. For Voronoi cells of two 
      and more molecules the time dependence of the velocity autocorrelation function 
      becomes monotonic and well reproduced by the respective MS-CG/DPD models. A 
      comparative analysis of force and velocity correlations in the atomistic and CG 
      ensembles indicates Markovian behavior with as low as two molecules per 
      dissipative particle. The models with one and two molecules per Voronoi cell 
      yield transport properties (diffusion and shear viscosity) that are in good 
      agreement with the atomistic data. The coarser models produce slower dynamics 
      that can be appreciably attributed to unaccounted dissipation introduced by 
      regular Voronoi re-partitioning as well as by larger numerical errors in mapping 
      out the dissipative forces. The framework presented herein can be used to develop 
      computational models of real liquids which are capable of bridging the atomistic 
      and mesoscopic scales.
FAU - Izvekov, Sergei
AU  - Izvekov S
AD  - U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA.
FAU - Rice, Betsy M
AU  - Rice BM
AD  - U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2014/03/19 06:00
MHDA- 2014/03/19 06:01
CRDT- 2014/03/18 06:00
PHST- 2014/03/18 06:00 [entrez]
PHST- 2014/03/19 06:00 [pubmed]
PHST- 2014/03/19 06:01 [medline]
AID - 10.1063/1.4866142 [doi]
PST - ppublish
SO  - J Chem Phys. 2014 Mar 14;140(10):104104. doi: 10.1063/1.4866142.