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Electronically coarse grained water Andrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna Problem Problem Intermolecular interactions depend on environment Challenge Develop simplest water model with electronic responses 1. Quantum

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Electronically coarse grained water

Andrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna

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Problem Challenge

Intermolecular interactions depend on environment Develop simplest water model with electronic responses

Problem

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1. Quantum Drude Oscillator (QDO)

Light negative particle tethered harmonically to heavy positive, oppositely charged nucleus Free parameters reduced mass spring constant charge

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Polarisabilities Dispersion coeffjcients

dipole dipole–dipole dipole–quadrupole

…

1. Quantum Drude Oscillator (QDO)

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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

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Dispersion

1.5 1.5 1.5 0.5 0.5 0.5 1 1 1 CH4 BH3 NH3 H2O He Ne Ar Kr Xe H Li K Rb Cs

2. The responses of QDOs are realistic

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3. QDO water

Frame: ground state charge distribution

+ 0.605 e

1.21 e

0.2667 Å 0.9572 Å

O H M H

104.52º

Frame: ground state charge distribution

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= 0.3656 amu = 0.6287 = -1.1973 e

3. QDO water

QDO: responses

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3. QDO water

Short range: empirical repulsion

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4. Liquid QDO water

Radial distribution function

r / Å

2345 67

gOO(r)

0.0 0.5 1.0 1.5 2.0 2.5

Skinner et al. (exp).

Exp. (Soper)

QDO, N = 300

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4. Liquid QDO water

Radial distribution function Vapour pressure

exp: 43.91 kJ/mol

r / Å

2345 67

gOO(r)

0.0 0.5 1.0 1.5 2.0 2.5

Skinner et al. (exp).

Exp. (Soper)

QDO, N = 300

46 ± 2 kJ / mol

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4. Liquid QDO water

Radial distribution function Vapour pressure

exp: 43.91 kJ/mol

r / Å

2345 67

gOO(r)

0.0 0.5 1.0 1.5 2.0 2.5

Skinner et al. (exp).

Exp. (Soper)

QDO, N = 300

46 ± 2 kJ / mol Dielectric constant

exp: 78

79 ± 2

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4. Liquid QDO water

Radial distribution function Vapour pressure

exp: 43.91 kJ/mol

r / Å

2345 67

gOO(r)

0.0 0.5 1.0 1.5 2.0 2.5

Skinner et al. (exp).

Exp. (Soper)

QDO, N = 300

46 ± 2 kJ / mol Dielectric constant

exp: 78

79 ± 2 Surface tension

exp: 71.73 mN / m

72.6 ± 1 mN / m

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5. Liquid–vapour interface of QDO water

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5. Liquid–vapour interface of QDO water

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5. Liquid–vapour interface of QDO water

loss & gain of electronic charge in bulk

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5. Liquid–vapour interface of QDO water

loss & gain of electronic charge at surface

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5. Liquid–vapour interface of QDO water

loss & gain of electronic charge last surface layer

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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

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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 water

Andrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna

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