Electronic structure simulations of water solid interfaces

Transcription

1 Electronic structure simulations of water solid interfaces Angelos Michaelides London Centre for Nanotechnology & Department of Chemistry, University College London Main co-workers: Javier Carrasco, Xinzheng Li, Brent Walker (UCL) Biswajit Santra, Matthias Scheffler (FHI) Ali Alavi (Cambridge), Matt Probert (York)

2 Hydrogen bonds are important, interesting, and still not well understood Temperature scale of life corresponds to energy to make and break hydrogen bonds... Today: i) Accuracy ii) Quantum nuclear dynamics R.E.A. Kelly et al, Small 4, 1494 (2008)

3 How good is DFT for hydrogen bonds? All functionals achieve chemical accuracy (1 kcal/mol ~ 43 mev). Variable performance with cluster size (especially the PBE family) No clear improved performance upon climbing Jacob s ladder. PBE0 and X3LYP are the best ; within 10 mev of MP2/CBS. B. Santra, A. Michaelides, and M. Scheffler, J. Chem. Phys. 127, (2007)

4 GGAs for liquid water: Much discussed overstructured O-O radial distribution functions Yoo et. al., JCP (2009), Morrone et al., PRL (2008); Kühne et al., JCTC (2009); Lee et al., JCP (2006, 2007); Schmidt et. al., JPCB (2009); Guidon et al., JCP (2008); Todorova et al., JPCB (2006); VandeVondele et al., JCP (2005); Grossman et al., JCP (2004); Fernández-Serra et al., JCP (2004); Morrone & Car, PRL (2008), Lin et al. JPCB (2009), and more [2] E. J. Bylaska et al., NWChem, Version 5.0 (2006).

5 GGAs for liquid water: overstructured O-O RDFs Step 1. MD simulation: BOMD 32 D 2 O XC: PBE GTH PP, 125 Ry T=330K 30 ps Code: CPMD [1] Step 2. Cluster calculations: Accurate reference: CBS DFT: PBE, BLYP, PBE0 66 dimers extracted Code: NWChem5.0 [2] Equilibrium From Gas Deformed From Liquid [1] J. Hutter et al., CPMD, version 3.11; [2] E. J. Bylaska et al., NWChem, Version 5.0 (2006).

6 Equilibrium Dimer from Gas Phase Binding Energy Monomer Deformation Interaction Energy Error [mev] PBE BLYP PBE0 PBE BLYP PBE0 PBE BLYP PBE0 Deformed Dimers from Liquid Phase Binding Energy Monomer Deformation Interaction Energy Error [mev] B. Santra, A. Michaelides, M. Scheffler, J. Chem. Phys. 129, (2009). PBE BLYP PBE0 PBE BLYP PBE0 PBE BLYP PBE0 B. Santra, A. Michaelides, M. Scheffler, J. Chem. Phys. 129, (2009).

7 B. Santra, A. Michaelides, and M. Scheffler, J. Chem. Phys. 127, (2007) B. Santra et al., J. Chem. Phys. 129, (2008) B. Santra, A. Michaelides, M. Scheffler, J. Chem. Phys. 129, (2009) J. Klimes, D.R. Bowler, A. Michaelides, J. Phys: Condens. Matter 22, (2010)

8 and now for something completely quantum Water Under Pressure Ice VIII Ice VII (>40 GPa) Ice X (>80 GPa) See e.g. M. Benoit, D. Marx, and M. Parrinello, Nature 392, 258 (1998); J.A. Morrone, L. Lin, and R. Car, J. Chem. Phys. 130, (2009)

9 Water-hydroxyl overlayers on metals Observed on Ru(0001), Rh(111), Pd(111), Cu(110), Pt(111) [first predicted with DFT: Michaelides & Hu, JACS 123, 4235 (2001); Feibelman, Science 295, 99 (2002)] Made by - water adsorption on the clean metal - water plus oxygen coadsorption - electric fields (electrochemistry) - reaction of hydrogen with oxygen Berzelius catalysis (1836) See e.g. A. Hodgson and S. Haq, Surf. Sci. Rep. 64, 381 (2009) STM: S. Volkening et al., Phys. Rev. Lett. 83, 2672 (1999)

10 Ab initio path integrals for water on metals The quantum mechanical partition function can be expressed as an integral over cyclic paths, represented by harmonically coupled beads on a chain... With quantum nuclei particles are delocalised in space & tunnel through barriers Feynman s cat: Born Oppenheimer MD implementation in CASTEP (Probert and co-workers) Planewaves, PPs, 3D periodic slab models, k points Exchange and correlation: PBE [Phys. Rev. Lett. 77, 3865 (1996)] 16 imaginary time replicas and 6,000 to 20,000 timesteps Ab initio PIMD: Marx, Tuckerman and coworkers: e.g. Marx and Parrinello, J. Chem. Phys. 104, 4077 (1996) CASTEP: S. J. Clark et al., Z. Kristallographie 567, 220 (2005).

11 Ab Initio MD with Classical Nuclei: H 2 O-OH/Pt(111) at 160 K DFT: Xinzheng Li See movie at or icelcn youtube channel

12 Classical picture: clear distinction between covalent and hydrogen bonds X.Z. Li, M.I.J. Probert, A. Alavi, A. Michaelides, Phys. Rev. Lett. 104, (2010). DFT: Xinzheng Li

13 Ab initio Path Integral MD: H 2 O-OH/Pt(111) at 160 K DFT: Xinzheng Li See movie at or icelcn youtube channel

14 Quantum picture: distinction between covalent and hydrogen bonds is lost Short Long Long X.Z. Li, M.I.J. Probert, A. Alavi, A. Michaelides, Phys. Rev. Lett. 104, (2010). DFT: Xinzheng Li

15 DFT: Xinzheng Li See movie at or icelcn youtube channel

16 DFT: Xinzheng Li Energy and dynamics/kinetics of proton transfer

17 Barrierless proton transfer for the most active proton Pt(111) Ru(0001) Ni(111) DFT: Xinzheng Li

18 3D Quantum Control of Hydrogen Bonds Temperature Lattice DFT: Xinzheng Li

19 Conclusions Benchmarks of xc functionals for H bonds and a novel explanation for overstructured RDF of water [JCP 127, ; 129, ; 129, ] Water-hydroxyl wetting layers exhibit strong quantum effects and provide a platform for further study of the quantum nature of hydrogen bonds [PRL 104, ] BISWAJIT JIRI BRENT XINZHENG Correlation between H bond strength and quantum nuclear dynamics identified Support Free game on itunes

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