物理与微电子科学学院学术报告
报告题目：Hidden Force in H2O
演讲人：孙长庆教授（新加坡南洋理工大学）
第一场报告时间：4月25日下午3点，
地点：集贤宾馆二楼第四会议室
欢迎参加!
ABSTRACT
Covering 70% of earth surface and 70% of weight of our body, H2O is too strange, too anomalous, and too challenge. In this presentation, I will share that an extension of the “Ice Rule” of Pauling has enabled us to make progress with a development of the “master-slave segmented hydrogen bond (O:H-O) (see figure)”, which allowed specification of the ultra-short-range interactions (O:H van der Walls interaction, H-O exchange interaction, and O--O inter-electron-pair Coulomb repulsion) and forces driving the asymmetric relaxation dynamics in water ice and its anomalies under various conditions.
It has been revealed that: i) Compression shortens-and-stiffens the softer “O:H” bond and the inter-electron-pair Coulomb repulsion lengthens-and-softens the stiffer “H-O” covalent bond, leading to the low compressibility, O:H-O proton symmetrization, phase-transition temperature (TC) depression, softer phonon (<300 cm-1) stiffening and stiffer phonon (>3000 cm-1) softening; ii) Molecular-undercoordination effects oppositely to compression due to the Goldschmidt-Pauling contraction of the H-O covalent bond, resulting in molecular volume expansion, melting point (viscosity) elevation, binding energy entrapment, bonding charge densification and nonbonding lone electron polarization, stiffer phonon stiffening and softer phonon softening of molecule clusters, surface skins, and ultrathin films of water that perform like ice and hydrophobic at the ambient temperature; iii) The disparity of the segmental specific heat discriminates the two parts in responding to cooling, which shortens alternatively the segments in liquid, solid, and transition phase. In the liquid and solid phases, the O:H bond (of lower specific heat) serves as the “master” that contracts largely and meanwhile forces the stiffer H-O bond as “slave” into Coulomb-repulsion-driven slight elongation, causing O--O contraction and the seemingly normal cooling densification of water and ice; at transition, the master-slave swap roles, turning the O--O into freezing elongation and volume expansion.
BIOGRAPHY
Dr Sun Changqing, received his Ph.D degree in 1996 at Murdoch University, Australia. He has been working on very-low-energy electron diffraction and STM/S analysis of H, C, N, O, and F chemisorption bonding dynamics, size dependence of nanostructures, and the thermo-mechanical behavior of low-dimensional systems with the development of a set of original theoretical, experimental, and numerical approaches including the bond-band-barrier correlation, bond border-length-strength correlation, nonbonding electron polarization, hydrogen bond asymmetric relaxation dynamics, local bond averaging approach, and the zone-resolved photoelectron quantitative spectroscopy (ZPS). He has published 250 journal articles including 8 themed reports in Chem Rev, Prog Mater Sci, and Prog Solid State Chem, etc., He was bestowed the 25th Khwarizmi International Award in 2012 and is currently on the Editorial Boards of 8 journals.
