Anders Nilsson , Stanford Synchrotron Radiation Lightsource Stockholm University

1. X-rays Shines Light on the Water Mystery Anders Nilsson, Stanford Synchrotron Radiation Lightsource Stockholm University

2. Lars Pettersson/Stockholm Matteo Cavalleri/Stockholm Michael Odelius/Stockholm Michael. Leetma/Stockholm Mathias. Ljungberg/Stockholm Thor Wikfeldt/Stockholm Lars Ojamäe/Linköping Takashi Tokushima/Spring8 Yoshihisa Harada/Spring8 Yuka Horikawa/Spring 8 Shik Shin/Tokyo Philippe Wernet/SSRL (BESSY) Congcong Huang/SSRL Uwe Bergmann/LCLS Hirohito Ogasawara/SSRL Dennis Nordlund/SSRL Lars Åke Näslund/SSRL Sarp Kaya/SSRL Ira Waluyo/SSRL-SU Chemistry Tomas Weiss/SSRL Ningdong Huang/SSRL-SU Applied Physics Trevor Mcqueen/SSRL-SU Chemistry Chen Chen/SSRL-SU Chemistry Jonas Sellberg/SSRL-Stockholm University Mike Bogan/PULSE Dmitri Starodub/PULSE Raymond Sierra/PULSE Coworkers, Funding and Experiments National Science Foundation (NSF) Department of Energy (DOE) Swedish Research Council (VR) Swedish Foundation for Strategic Research (SFF) Experiments: SSRL (4.0, 6.2, 5.1, 4-2) APS (BioCat beamline), ALS beamline (8.0, 11.0), Spring 8 and MAXlab (511)

3. The Blue Planet

4. Access to Clean Water The Challenge for the World with Climate Change Climate Change Water Issues Gore, Inconvenient Truth

5. Water denser than ice Density of the liquid higher than the solid Normal liquid (ethanol, gasoline,etc) Solid more dense than liquid

6. density dddddddddddd Ssssssssssssssssssssssss -50 -25 0 25 50 75 100 Temperature/ °C Density Maximum Normal liquid Water At the bottom of the glass is 4 °C water

7. High Heat Capacity The amount of heat to add for the temperature to rise 1°C It stabilizes the temperature in the Oceans Ocean current stabilizes the climate

8. High Surface Tension Water has extremely high surface tension Spiders can walk on water Water droplets can form

9. Anomalous Properties of Water Thermal expansion Density <(S V)>=VkBT Isothermal Compressibility Heat Capacity <(V)2>=VkBTT <(S)2>=NkBcp . [P. G. Debenedetti, J. Phys.: Condens. Matter15, R1669 (2003)]

10. Temperature °C 100 H2O H2Po 50 Room Temp H2Te 0 H2Se -50 H2S SnH4 -100 GeH4 SiH4 -150 CH4 -200 0 50 100 150 200 250 Molecular mass Periodic table High boiling point Boiling points Water should be a gas at room temperature Why not?

11. The Hydrogen Bond O-H chemical bonds Positive H atoms Negative O atoms Lone pairs d + d - ssssssssssssssssssssssssssssssss ddddddd Ddd Ssssssssssssssss d - d + 2 Å 1 Å Ssssssssssssssssssssssssssssssss electrostatic interaction

12. Tetrahedral Coordination d + d - Oxygen Hydrogen

13. Ice Open spaces where no molecules are present If molecules move to fill the open space there will be an increase in the density

14. What is Water? What is Water

15. X-ray Absorption electron Inner Outer orbit nucleus

16. X-ray Emission electron Inner Outer orbit nucleus

17. XES hn X-ray Emission spectroscopy 1b2 3a1 1b1 1b2 4a1 1b1 Gas 3a1 1b2 2a1 Liquid O1s Tokushima et al., Chem. Phys. Lett. 460(2008) 387

18. Outer hv Inner Increasing hydrogen bonding X-ray Emission Spectroscopy Gas Energy Ice Tokushima et al., Chem. Phys. Lett. 460(2008) 387

19. Outer hv Inner Gas X-ray Emission Spectroscopy Increasing hydrogen bonding A very homogeneous water model Energy Ice Tokushima et al., Chem. Phys. Lett. 460(2008) 387

20. Outer hv Inner Increasing hydrogen bonding X-ray Spectroscopy Gas WATER Two Peaks !!! Two different components Energy Ice Tokushima et al., Chem. Phys. Lett. 460(2008) 387

21. Outer hv Inner Gas X-ray Spectroscopy Increasing hydrogen bonding Energy Ice Tokushima et al., Chem. Phys. Lett. 460(2008) 387

22. Temperature Dependence • Intensity transferred tetrahedral to disordered as temperature is increased (fewer H-bonds) • NO broadening, NO new peaks: Either tetrahedral OR very disordered Tokushima et al., Chem. Phys. Lett. 460(2008) 387 Huang et al., PNAS. 106 (2009) 15214

23. Temperature Changes of Distorted Component • Distorted species changes with temperature • Tetrahedral fixed Shifts towards gas phase with increasing temperature Fixed Huang et al., PNAS. 106 (2009) 15214

24. Summary X-ray Emission Spectroscopy • Tetrahedral loses intensity with • temperature, but peak at fixed energy • Distorted gains intensity and disperses • with temperature • Energy taken up through: • - Thermal excitation of distorted species • - Breaking up a fraction of tetrahedral • species 20-30 % 70-80 % Tokushima et al., Chem. Phys. Lett. 460(2008) 387 Huang et al., PNAS. 106 (2009) 15214

25. Bonds vs. Entropy localized bonds delocalized bonds Bond Energy Entropy

26. λ Two Types – Inhomogeneous?Small-Angle X-ray Scattering (SAXS) Small angles “trick” the light that distances are short Projection… λ Measures density contrast Size of macromolecules, colloids etc (Guinier analysis) Critical density fluctuations (Ornstein-Zernike) d d d ~ 2π/Q

27. Theoretical curve for single component Very Homogeneous SPC/E

28. Surprising experimental result Hypothetical Water Homogeneous Experimental Water Minimum related to size Enhancement showing heterogeneity small regions Huang et al., PNAS. 106 (2009) 15214

29. Q<<1) F.T. gA(r)~exp(-r/ζ)/r (r>>1) The isothermal compressibility T Very good fit to previous data Huang et al., PNAS 106, 15214 (2009); PNAS 107, E45 (2010); JCP 133, 134504 (2010) SAXS – Ambient to Supercooled Regime At low Q range S(Q) shows an unusual enhancement Much larger enhancements (fluctuations!) at lower T

30. Snapshot from MD at 253K Grey: High tetrahedrality Red: High density Note: XES sees very little intermediate species Wikfeldt et al., unpublished

31. Dance Restaurant People at the table are more socially bonded, local order, low density People dancing are disordered but excited and moves around, higher density Exchange between dancing and sitting people

32. Cooling lowering temperature Bond Energy in Tetrahedral becomes more important Converting some Disordered structures to ice-like structures

33. Phase Diagram of Water and Ice 15 Ice Polymorphs 2 Amorphous Ices LDA & HDA,VHDA HDA Widom Line LDA C2 (HDA)=1.17 g/cm3 (VHDA)=1.25 (LDA)=0.94 (Ih)=0.92 (Ic)=0.92 (C1)=0.322 C1 t

34. Widom Line and 2nd Critical Point The Widom line is an extension of the coexistence line beyond the critical point. Thermodynamical properties have maxima but do not diverge along this line

35. Fit ζ to (apparent) powerlaw with .32 .52 Apparent Power Law – Widom Line Critical phenomena characterized by power laws with critical exponents 2nd critical point scenario Fluctuations between HDL/LDL Poole et al., Nature 360, 324 (1992) Poole et al., Nature 360, 324 (1992) Huang et al. JCP 133, 134504 (2010)

36. Water denser than the solid Water, higher density Disordered structure allows more dense packing Ice, lower density More open space Open space inside the rings

37. density dddddddddddd Ssssssssssssssssssssssss -50 -25 0 25 50 75 100 Temperature/ °C 4 °C Density Maximum Tetrahedral lower density Disordered higher density

38. density dddddddddddd Ssssssssssssssssssssssss -50 -25 0 25 50 75 100 Temperature/ °C Density Maximum Tetrahedral lower density Disordered higher density With decreasing temperature we increase the number of tetrahedral structures which have lower density

39. High Heat Capacity It stabilizes the temperature in the Oceans Much of the extra heat is used to convert the tetrahedral structures to the disordered without increasing the kinetic energy of the particles

40. Temperature °C 100 H2O H2Po 50 Room Temp H2Te 0 H2Se -50 H2S SnH4 -100 GeH4 SiH4 -150 CH4 -200 0 50 100 150 200 250 Molecular mass High Surface Tension Boiling points Molecular mass makes gasoline a liquid but weak bonding in between the molecules Hydrogen bonds in water makes the glue

41. The important aspects in my lecture Two local structures Ice-like low density (low energy, low entropy) Disordered high density (high energy, high entropy) Fluctuations on a 1nm length scale Increases with decreasing temperature

42. Water is maybe not so strange but special