The specific heat curves in FIG. to approximately 3450 cm -1 . The skins of water and ice , the ionic hydration cell , and the electrified water bridge share the same H-O bonding identity of undercoordination. An ultra-violet photoelectron spectroscopy examination uncovered that electronic hydration and molecular undercoordination of water droplets lowers the bound energy of a hydrated electron from 2.4 to 1.2 and 0.4 eV when moves from the centre to the skin of a droplet and a (H2O)5 cluster. The PDPS analysis of 5% deuterium-contained water droplets ranging from 1.7 to 4.0 nm in size showed that the D-O bond within the skin shell, which is 0.295 nm thick, contracts by 10% from its bulk value of 0.10 nm. This D-O contraction leads to a blue shift in the D-O vibration frequency, from around 2480 to 2600 cm -1 , and the H-O phonon lifetime from 2.6 ps for bulk to 50 ps for the 1.7 nm droplet . ). Theoretical reproduction of the pressure-induced (e) T m depression and (f) T N and T V elevation resolves the H-O cohesive energy dominance of ice regelation and O:H energy dominance of the instant ice formation .