Electronically coarse grained water Andrew Jones Flaviu Cipcigan Vlad - PowerPoint PPT Presentation

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 Drude Oscillator (QDO) Light negative particle tethered harmonically to heavy positive , oppositely charged nucleus Free parameters reduced mass spring constant charge

1. Quantum Drude Oscillator (QDO) Polarisabilities dipole Dispersion coeffjcients dipole–dipole dipole–quadrupole …

2. The responses of QDOs are realistic 1.5 CH 4 H 2 O 1 0.5 Polarisation 1.5 Kr Xe He Ne Ar 1 0.5 1.5 H K Rb Cs Li 1 0.5

2. The responses of QDOs are realistic BH 3 CH 4 1.5 NH 3 H 2 O 1 0.5 Dispersion 1.5 Kr Xe He Ne Ar 1 0.5 H K Rb Cs 1.5 Li 1 0.5

3. QDO water Frame : ground state charge distribution Frame : ground state charge distribution 0.9572 Å - 1.21 e O 0.2667 Å M + 0.605 e 104.52º H H

3. QDO water QDO : responses = 0.3656 amu = 0.6287 = -1.1973 e

3. QDO water Short range : empirical repulsion

4. Liquid QDO water Radial distribution function Skinner et al. (exp). 2.5 Exp. (Soper) QDO, N = 300 2.0 g OO ( r ) 1.5 1.0 0.5 0.0 2345 67 r / Å

4. Liquid QDO water Radial distribution function Vapour pressure 46 ± 2 kJ / mol Skinner et al. (exp). exp: 43.91 kJ/mol 2.5 Exp. (Soper) QDO, N = 300 2.0 g OO ( r ) 1.5 1.0 0.5 0.0 2345 67 r / Å

4. Liquid QDO water Radial distribution function Vapour pressure 46 ± 2 kJ / mol Skinner et al. (exp). exp: 43.91 kJ/mol 2.5 Exp. (Soper) QDO, N = 300 Dielectric constant 2.0 g OO ( r ) 79 ± 2 1.5 exp: 78 1.0 0.5 0.0 2345 67 r / Å

4. Liquid QDO water Radial distribution function Vapour pressure 46 ± 2 kJ / mol Skinner et al. (exp). exp: 43.91 kJ/mol 2.5 Exp. (Soper) QDO, N = 300 Dielectric constant 2.0 g OO ( r ) 79 ± 2 1.5 exp: 78 1.0 Surface tension 0.5 72.6 ± 1 mN / m 0.0 2345 67 exp: 71.73 mN / m r / Å

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 charge in bulk

5. Liquid–vapour interface of QDO water loss & gain of electronic charge at surface

5. Liquid–vapour interface of QDO water loss & gain of electronic charge last surface layer

6. Conclusions QDO water model of the isolated molecule , condensed properties emerge naturally simple, but with a complex electronic structure transferability may be good, under investigation

Electronically coarse grained water Andrew Jones Flaviu Cipcigan Vlad Sokhan Jason Crain Glenn Martyna 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)