Post on 05-Feb-2021
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Electronically coarse grained waterAndrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna
Problem
Challenge
Intermolecular interactions depend on environment
Develop simplest water model with electronic responses
Problem
1. Quantum Drude Oscillator (QDO)Light negative particle tethered harmonically to heavy positive, oppositely charged nucleus
Free parameters
reduced mass
spring constant
charge
Polarisabilities
Dispersion coefficients
dipole
dipole–dipole
dipole–quadrupole
…
1. Quantum Drude Oscillator (QDO)
2. The responses of QDOs are realistic
CH4 H2O
He Ne Ar Kr Xe
H Li K Rb Cs
1.5
1.5
1.5
0.5
0.5
0.5
1
1
1
Polarisation
Dispersion
1.5
1.5
1.5
0.5
0.5
0.5
1
1
1
CH4
BH3 NH
3 H2O
He Ne Ar Kr Xe
H Li K Rb Cs
2. The responses of QDOs are realistic
3. QDO waterFrame: ground state charge distribution
+ 0.605 e
- 1.21 e
0.2667 Å0.957
2 ÅO
H
M
H 104.52º
Frame: ground state charge distribution
= 0.3656 amu
= 0.6287
= -1.1973 e
3. QDO waterQDO: responses
3. QDO waterShort range: empirical repulsion
4. Liquid QDO water
Radial distribution function
r / Å2345 67
g OO(r
)
0.0
0.5
1.0
1.5
2.0
2.5Skinner et al. (exp).Exp. (Soper)QDO, N = 300
4. Liquid QDO water
Radial distribution function Vapour pressure
exp: 43.91 kJ/mol
r / Å2345 67
g OO(r
)
0.0
0.5
1.0
1.5
2.0
2.5Skinner et al. (exp).Exp. (Soper)QDO, N = 300
46 ± 2 kJ / mol
4. Liquid QDO water
Radial distribution function Vapour pressure
exp: 43.91 kJ/mol
r / Å2345 67
g OO(r
)
0.0
0.5
1.0
1.5
2.0
2.5Skinner et al. (exp).Exp. (Soper)QDO, N = 300
46 ± 2 kJ / mol
Dielectric constant
exp: 7879 ± 2
4. Liquid QDO water
Radial distribution function Vapour pressure
exp: 43.91 kJ/mol
r / Å2345 67
g OO(r
)
0.0
0.5
1.0
1.5
2.0
2.5Skinner et al. (exp).Exp. (Soper)QDO, N = 300
46 ± 2 kJ / mol
Dielectric constant
exp: 7879 ± 2
Surface tension
exp: 71.73 mN / m72.6 ± 1 mN / m
5. Liquid–vapour interface of QDO water
5. Liquid–vapour interface of QDO water
5. Liquid–vapour interface of QDO water
loss & gain of electronic chargein bulk
5. Liquid–vapour interface of QDO water
loss & gain of electronic chargeat surface
5. Liquid–vapour interface of QDO water
loss & gain of electronic chargelast surface layer
6. Conclusions
simple, but with a complex electronic structure
transferability may be good, under investigation
QDO water
model of the isolated molecule, condensed properties emerge naturally
A. Jones, Quantum drude oscillators for accurate many-body intermolec-ular forces, PhD thesis, The University of Edinburgh
A. Jones, F. Cipcigan, V. Sokhan, J. Crain, G. Martyna, Electronically coarse grained model for water, PRL 110, 227801 (2013)
Electronically coarse grained waterAndrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna