SI-ppt-Movie.pptx

A Supersolid Skin Covering both Water and Ice.

https://arxiv.org/submit/902255

The mysterous nature and functionality of wter and ice skins remain baffling to thecomnminity since 1985s, the age of Farady. Here we verify our predictions on the skin supersolidity of both water and ice by analysing Raman measurments and quantum calculations. In the skin of two molecular layers, molecular undercoordination shortens the H-O bond by ~16% and lengthens the O:H nonbond by ~25% through inter electron-pair repulsion, which depresses the density from 0.92 for bulk ice to 0.75 g×cm^-3. The cooperative relaxation of the O:H-O bond stiffens the H-O stretching phonon from 3200/3150 cm^-1 to the same value of 3450 cm^-1 for skins of both water and ice with electronic bounding energy (similar to work function) reduction. Numerical exploitation on the viscoecity and charge accuumulation suggests that the elastic, polarized, and thermally stable supersolid phase makes the ice frictionless and water skin hydrophobic and ice like at room temperature.