Charge Transfer between Water Molecules As the Possible Origin of the Observed Charging at the Surface of Pure Water
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- 作者：Robert V谩cha ; Ondrej Marsalek ; Adam P. Willard ; Douwe Jan Bonthuis ; Roland R. Netz ; Pavel Jungwirth
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2012
- 出版时间：January 5, 2012
- 年：2012
- 卷：3
- 期：1
- 页码：107-111
- 全文大小：287K
- 年卷期：v.3,no.1(January 5, 2012)
- ISSN：1948-7185
文摘
Classical molecular dynamics simulations point to an anisotropy of water鈥搘ater hydrogen bonding at the water surface. Approaching from the gas phase, a region of primarily dangling hydrogens is followed by dangling oxygens before the isotropic bulk region. Using ab initio calculations, we translate this hydrogen bonding anisotropy to charge transfer between water molecules, which we analyze with respect to both instantaneous and averaged positions of the water surface. Similarly to the oil/water interface, we show that there is a region of small net negative charge extending 0.2 to 0.6 nm from the Gibbs dividing surface in the aqueous phase. Using a simple continuum model, we translate this charge profile to a zeta potential, which acquires for realistic positions of the shear surface the same negative sign as that observed experimentally, albeit of a smaller absolute value.