1
Interface MD
Validation
July 15, 2017
Hendrik HeinzDepartment of Chemical and Biological
EngineeringMaterials Science and Engineering Program
University of Colorado-Boulder, CO, USA
2
Validation Overview
• Lattice parameters are usually
3
Clay-Water Interfaces – Example Pyrophyllite
Giese et al., Phys. Chem. Miner. 1991, 17, 611-616
• No spreading and some hydrophobicity
- note absence of Na+ ions
• Contact angle θ = 80 ±5º in equilibrium
Experiment: θ = 79.2 ±7.4º
CLAYFF: θ = 105 ±5º X
Si Al
O H
CEC = 0
meq/100g
CHARMM-IFF
4
Metal-Organic Interfaces: Comparison of DFT (M06)
and IFF
Gupta et al. J. Phys. Chem. C 2016, 120, 17454.
CHARMM-IFF
DFT (M06-L)
5
Also lipids free energies on gold
~10% agreement with expt –Quirke et al. Chem. Phys. Lett. 2016, 664, 199;
Horsewell et al. Faraday Disc. 2002, 121, 405.
Match Between DFT and IFF Better than 10%
Gupta et al. J. Phys. Chem. C 2016, 120, 17454.
6
Peptide Binding to Silica Surfaces in Solution
at Different pH
Adsorption isotherm (experiment) Simulation (CHARMM-IFF)
0
20
40
60
80
100
50 18 9 09 7 5 3
Approx. pH
Surface ionization (%)
LDHSLHS (-)
AFILPTG (=)
KLPGWSG (+)
Tim
e in
clo
se c
onta
ctw
ith s
urfa
ce (
%)
0
2
4
6
8
10
8.5 7.4 5 3
LDHSLHS (-)
AFILPTG (=)
Adsorb
ed a
mount
(peptides p
er
nm
2 )
KLPGWSG (+)
pH
F. S. Emami, C. C. Perry, H. Heinz, et al. Chem. Mater. 2014, 26, 5725.
• Free energies of binding range from -8 kcal/mol to 0 kcal/mol in experiment and
are reproduced with ±1 kcal/mol precision in the simulationFFSiOH fails X
7
Lattice Parameters - Examples
• Computed unit cell parameters (NPT dynamics) agree ±0.5% with experimental X-Ray crystal structures (previously ±3-5%)
Example compounds cell
dim.
a
(nm)
b
(nm)
c
(nm)
α
(°)β
(°)γ
(°)V
(nm3)
rms dev
(pm/atom)
Mica
K2Si6Al6O20(OH)4
exp
sim
531 2.596
2.585
2.705
2.691
2.005
2.006
90
89.54
95.73
95.36
90
90.01
14.00
13.89
0
15
Hydroxyapatite
Ca10(PO4)6(OH)2
exp
sim
222 1.883
1.882
1.883
1.881
1.375
1.375
90.00
90.00
90.00
90.00
120.0
120.0
4.224
4.214
0
20
Gypsum
CaSO4 · 2 H2O
exp
sim
313 1.703
1.703
1.521
1.521
1.886
1.856
90.0
90.0
114.08
112.1
90.0
90.0
4.462
4.455
0
26
Tobermorite 11 Å
Ca4Si6 O15(OH)2 · 5 H2O
exp
sim
221 1.347
1.348
1.477
1.467
2.249
2.247
90
89.55
90
90.15
123.25
123.13
3.741
3.721
0
23
Gold
Au
exp
sim
555 2.039
2.039
2.039
2.039
2.039
2.039
90.0
90.0
90.0
90.0
90.0
90.0
8.478
8.477
0
1
8
Cleavage Energy and Modulus – Examples
Heinz, Emami, et al. Langmuir Feature 2013, 29, 1754.::
::
::
9
Hydration Energy as a Function of pH -
Hydroxyapatite
T. J. Lin, H. Heinz J. Phys. Chem. C 2016, 120, 4975. Chem. Soc. Rev. 2016, 45, 412.
different
mechanisms
15 10 5
Cleavage
energy
comp
expt 1000-1200 350-500
Immersion
energy in
water
reactive
600-700
Eb ~ -4.7
kcal/mol
(010)
• C-term.
• NH3+ at K7
Adsorption
of peptide
SVSVGGK
(010)
Eb ~ -9.0
kcal/mol
• S1, S3
Ca P O C N H
pH
• V2, V4
(identified by
phage display)
10
Influence of Chosen Energy Expression is Small –
Example Tricalcium Aluminate
Sometimes 5-10% lower modulus and cleavage energy using 9-6 LJ
potential (PCFF) vs 12-6 LJ potential (CHARMM etc)
Mishra, Heinz et al. Dalton Trans. 2014, 43, 10602.
11
References by Type of Compound
Below is a list of references that introduce and validate the force fields. Citing references to these papers
need also be followed for details as many groups have meanwhile used IFF and added to the validation.
• Clay minerals/layered silicates: J. Am. Chem. Soc. 2003, 125, 9500-9510. DOI: 10.1021/ja021248m. Chem. Mater. 2005, 17,
5658. DOI: 10.1021/cm0509328. J. Chem. Phys. 2006, 124, 224713. DOI: 10.1063/1.2202330. Chem. Mater. 2007, 19, 59-
68. DOI: 10.1021/cm062019s. J. Phys. Chem. C 2010, 114, 1763-1772. DOI: 10.1021/jp907012w. Chem. Mater. 2010, 22,
1595-1605. DOI: 10.1021/cm902784r. J. Phys. Chem. C 2011, 115, 22292-22300. DOI: 10.1021/jp208383f.
• Fcc metals: J. Phys. Chem. C 2008, 112, 17281-17290. DOI: 10.1021/jp801931d. J. Am. Chem. Soc. 2009, 131, 9704-9714.
DOI: 10.1021/ja900531f. Phys. Chem. Chem. Phys. 2009, 11, 1989-2001. DOI: 10.1039/B816187A. J. R. Soc. Interface
2011, 8, 220-232. DOI: 10.1098/rsif.2010.0318. Soft Matter 2011, 7, 2113-2120. DOI: 10.1039/C0SM01118E. J. Am. Chem.
Soc. 2011, 133, 12346-12349. DOI: 10.1021/ja203726n. Small 2012, 8, 1049-1059. DOI: 10.1002/smll.201102066. Nano
Lett. 2013, 13, 840-846. DOI: 10.1021/nl400022g. Many further recent papers.
• Silica: J. Am. Chem. Soc. 2012, 134, 6244-6256. DOI: 10.1021/ja211307u. Chem. Mater. 2014, 26, 2647-2658. DOI:
10.1021/cm500365c. Chem. Mater. 2014, 26, 5725-5734. DOI: 10.1021/cm5026987.
• Hydroxyapatite: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846. J. Phys. Chem. C 2016, 120, 4975-4992. DOI:
10.1021/acs.jpcc.5b12504.
• Cement minerals/LDH: J. Phys. Chem. C 2013, 117, 10417-10432. DOI: 10.1021/jp312815g. Langmuir 2013, 29, 1754-1765.
DOI: 10.1021/la3038846. Dalton Trans. 2014, 43, 10602-10616. DOI: 10.1039/C4DT00438H.
• Calcium sulfates: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846.
• Poly(ethylene oxide): Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846.
• Overview papers: Langmuir 2013, 29, 1754-1765. DOI: 10.1021/la3038846. Chem. Soc. Rev. 2016, 45, 412-448. DOI:
10.1039/C5CS00890E. For clays only: Clay Miner. 2012, 47, 205-230. DOI: 10.1180/claymin.2012.047.2.05.
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