PMID- 23943352
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20150629
LR  - 20150501
IS  - 1439-7641 (Electronic)
IS  - 1439-4235 (Linking)
VI  - 14
IP  - 14
DP  - 2013 Oct 7
TI  - Comparison of force fields on the basis of various model approaches--how to 
      design the best model for the [CnMIM][NTf2] family of ionic liquids.
PG  - 3368-74
LID - 10.1002/cphc.201300486 [doi]
AB  - In this contribution, we present two new united-atom force fields (UA-FFs) for 
      1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C(n)MIM][NTf(2)] 
      (n=1, 2, 4, 6, 8) ionic liquids (ILs). One is parametrized manually, and the 
      other is developed with the gradient-based optimization workflow (GROW). By doing 
      so, we wanted to perform a hard test to determine how researchers could benefit 
      from semiautomated optimization procedures. As with our already published 
      all-atom force field (AA-FF) for [C(n)MIM][NTf(2)] (T. Koddermann, D. Paschek, R. 
      Ludwig, ChemPhysChem- 2007, 8, 2464), the new force fields were derived to fit 
      experimental densities, self-diffusion coefficients, and NMR rotational 
      correlation times for the IL cation and for water molecules dissolved in 
      [C(2)MIM][NTf(2)]. In the manual force field, the alkyl chains of the cation and 
      the CF3 groups of the anion were treated as united atoms. In the GROW force 
      field, only the alkyl chains of the cation were united. All other parts of the 
      structures of the ions remained unchanged to prevent any loss of physical 
      information. Structural, dynamic, and thermodynamic properties such as viscosity, 
      cation rotational correlation times, and heats of vaporization calculated with 
      the new force fields were compared with values simulated with the previous AA-FF 
      and the experimental data. All simulated properties were in excellent agreement 
      with the experimental values. Altogether, the UA-FFs are slightly superior for 
      speed-up reasons. The UA-FF speeds up the simulation by about 100 % and reduces 
      the demanded disk space by about 78 %. More importantly, real time and efforts to 
      generate force fields could be significantly reduced by utilizing GROW. The real 
      time for the GROW parametrization in this work was 2 months. Manual 
      parametrization, in contrast, may take up to 12 months, and this is, therefore, a 
      significant increase in speed, though it is difficult to estimate the duration of 
      manual parametrization.
CI  - Copyright (c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
FAU - Koddermann, Thorsten
AU  - Koddermann T
AD  - Fraunhofer Institut fur Algorithmen und wissenschaftliches Rechnen, Schloss 
      Birlinghoven, 53754 Sankt Augustin (Germany). koeddermann@scai.fraunhofer.de.
FAU - Reith, Dirk
AU  - Reith D
FAU - Ludwig, Ralf
AU  - Ludwig R
LA  - eng
PT  - Journal Article
DEP - 20130813
PL  - Germany
TA  - Chemphyschem
JT  - Chemphyschem : a European journal of chemical physics and physical chemistry
JID - 100954211
OTO - NOTNLM
OT  - GROW
OT  - force fields
OT  - ionic liquids
OT  - molecular dynamics
OT  - quantum mechanics
EDAT- 2013/08/15 06:00
MHDA- 2013/08/15 06:01
CRDT- 2013/08/15 06:00
PHST- 2013/05/17 00:00 [received]
PHST- 2013/08/15 06:00 [entrez]
PHST- 2013/08/15 06:00 [pubmed]
PHST- 2013/08/15 06:01 [medline]
AID - 10.1002/cphc.201300486 [doi]
PST - ppublish
SO  - Chemphyschem. 2013 Oct 7;14(14):3368-74. doi: 10.1002/cphc.201300486. Epub 2013 
      Aug 13.