PMID- 20707563
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20101227
LR  - 20100816
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 133
IP  - 6
DP  - 2010 Aug 14
TI  - The multiscale coarse-graining method: assessing its accuracy and introducing 
      density dependent coarse-grain potentials.
PG  - 064109
LID - 10.1063/1.3464776 [doi]
AB  - The ability of particle-based coarse-grain potentials, derived using the recently 
      proposed multiscale coarse-graining (MS-CG) methodology [S. Izvekov and G. A. 
      Voth, J. Phys. Chem. B 109, 2469 (2005); J. Chem. Phys. 123, 134105 (2005)] to 
      reconstruct atomistic free-energy surfaces in coarse-grain coordinates is 
      discussed. The MS-CG method is based on force-matching generalized forces 
      associated with the coarse-grain coordinates. In this work, we show that the 
      MS-CG method recovers only part of the atomistic free-energy landscape in the 
      coarse-grain coordinates (termed the potential of mean force contribution). The 
      portion of the atomistic free-energy landscape that is left out in the MS-CG 
      procedure contributes to a pressure difference between atomistic and coarse-grain 
      ensembles. Employing one- and two-site coarse-graining of nitromethane as worked 
      examples, we discuss the virial and compressibility constraints to incorporate a 
      pressure correction interaction into the MS-CG potentials and improve performance 
      at different densities. The nature of the pressure correction interaction is 
      elucidated and compared with those used in structure-based coarse-graining. As 
      pairwise approximations to the atomistic free-energy, the MS-CG potentials 
      naturally depend on the variables describing a thermodynamic state, such as 
      temperature and density. Such dependencies limit state-point transferability. For 
      nitromethane, the one- and two-site MS-CG potentials appear to be transferable 
      across a broad range of temperatures. In particular, the two-site models, which 
      are matched to low and ambient temperature liquid states, perform well in 
      simulations of the ambient crystal structure. In contrast, the transferability of 
      the MS-CG models of nitromethane across different densities is found to be 
      problematic. To achieve better state-point transferability, density dependent 
      MS-CG potentials are introduced and their performance is examined in simulations 
      of nitromethane under various thermodynamic conditions, including shocked states.
FAU - Izvekov, Sergei
AU  - Izvekov S
AD  - U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA. 
      sergiy.izvyekov@us.army.mil
FAU - Chung, Peter W
AU  - Chung PW
FAU - Rice, Betsy M
AU  - Rice BM
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2010/08/17 06:00
MHDA- 2010/08/17 06:01
CRDT- 2010/08/17 06:00
PHST- 2010/08/17 06:00 [entrez]
PHST- 2010/08/17 06:00 [pubmed]
PHST- 2010/08/17 06:01 [medline]
AID - 10.1063/1.3464776 [doi]
PST - ppublish
SO  - J Chem Phys. 2010 Aug 14;133(6):064109. doi: 10.1063/1.3464776.