Supporting Information
Size, separation, structural order, and mass density of molecules
packing in water and ice
CQ Sun, Yongli Huang, Xi Zhang, Zengsheng Ma, Wen Li, Yichun Zhou, Ji Zhou and Weitao Zheng
E-mail: Ecqsun@ntu.edu.sg
Nomenclature
Electron pairs on oxygen
DFT derived charge distribution in the cross-section of
a unit cell of the ice-IIIV phase [1]. Red colour
represents for electron pairs and the blue for O ion
cores. The electron pairs are strongly and eccentrically
localized. This configuration pertains in liquid water
because of the fact that the O:H and the H-O stretching
phonons shift cooperatively. One segment becomes
shorter and stiffer; the other will be longer and softer.
Short-range
Interactions are within the shaded region only [2]:
1. Intermolecular H:O van der Waals (vdW)
interaction
2. Intramolecular H-O exchange interaction
3. Inter-electron-pair O---O Coulomb repulsion
(C-repulsion)
4. vdW potential is estimated at EL ~ 0.1 eV and
the H-O bond energy at ~4.0 eV.
5. Interactions switch off out the shaded
boundaries.
interactions
Fig S1 (T) of water measured using (a) Raman and FTIR (1.4 nm) [3] and (b) small-angle scattering of xrays (SAXS) [4].
2.2
P
T
Refs
Fit
dL(Å)
2.0
1.8
1.6
1.4
1.2
1.0
Equation
y = A1*exp(-x/t1) + y0
Adj. R-Square
0.99792
Value
Standard Error
H
y0
2.56214
0.03947
H
A1
-0.01409
0.00303
H
t1
-0.24275
0.00997
0.8
0.9
1.0
1.1
dH(Å)
Fig S2 Fitting parameters and reliability (R-factor) of Fig 3 in main text.
1.
2.
3.
4.
C.Q. Sun, X. Zhang, and W.T. Zheng, Hidden force opposing ice compression. Chem Sci, 2012. 3:
1455-1460.
Y. Huang, X. Zhang, and C.Q. Sun, et al., Potential paths for O:H-O bond proton symmetrization.
http://arxiv.org/abs/1305.2997, Communicated.
F. Mallamace, C. Branca, M. Broccio, C. Corsaro, C.Y. Mou, and S.H. Chen, The anomalous
behavior of the density of water in the range 30 K < T < 373 K. PNAS, 2007. 104(47): 1838718391.
M. Erko, D. Wallacher, A. Hoell, T. Hauss, I. Zizak, and O. Paris, Density minimum of confined
water at low temperatures: a combined study by small-angle scattering of X-rays and neutrons.
PCCP, 2012. 14(11): 3852-3858.