竞彩足球比分

报告题目：Oxidation States under Pressure: Challenging Two Long-Held Paradigms

报告嘉宾：John S. Tse，加拿大萨斯喀彻温大学 教授

报告时间：2026年9月15日 14：30

报告地点：吉林大学中心校区唐敖庆楼B区521报告厅

主持人：刘寒雨

报告摘要

Oxidation state is one of the most powerful qualitative concepts in chemistry. It provides a useful framework for describing electron transfer, bonding, and chemical reactivity, although it is not equivalent to the actual charge or ionicity of an atom. Under high pressure, however, extension of this familiar interpretation becomes less straightforward. Compression substantially increases orbital overlap and introduces strong interactions between neighbouring atoms, leading to electron redistribution, charge delocalization, and changes in bonding that may not occur under ambient condition.

In this presentation, two long-held concepts are critically examined: the assignment of oxidation states in iron-bearing minerals and the interpretation of pressure-induced valence changes in the lanthanides. Experimental observations are combined with first-principles electronic-structure calculations to distinguish formal oxidation states from measurable changes in charge density and orbital occupation. The results show that the assignment of oxidation state can become ambiguous under strong compression and may not reliably represent the actual valence-electron configuration or chemical behaviour of an atom.

嘉宾简介

Professor John S. Tse is a materials scientist whose career spans chemistry, physics, computational materials science, synchrotron science, mineral physics, and high-pressure research. He integrates first-principles electronic-structure calculations with high-pressure experiments using neutron and synchrotron X-ray spectroscopy to understand material behaviour.

Professor Tse earned his B.Sc. in Chemistry from The Chinese University of Hong Kong and his Ph.D. in Chemistry from the University of Western Ontario. He began his research career at the National Research Council of Canada, where he became a Principal Research Officer and led the Theory and Computational Project. In 2004, he joined the University of Saskatchewan as a Tier I Canada Research Chair in Synchrotron Science, and he is now a University Distinguished Professor.

Professor Tse’s scientific work covers a broad range of cross-disciplinary subjects. He has made contributions across several major areas of condensed-matter and materials physics. In clathrate hydrates, he established the molecular mechanisms governing gas trapping and hydrate nucleation, providing fundamental insight into energy storage and planetary ices. In ice physics, his work on amorphous and high-pressure ice revealed the structural origin of water polyamorphism and the transformations between crystalline and amorphous phases, advancing our understanding of water under extreme conditions. In thermoelectric materials, he developed first-principles theories linking electronic structure, lattice dynamics, and anharmonic phonon transport to the design of high-efficiency thermoelectrics with low thermal conductivity. In high-pressure superconductivity, he conducted quantum-mechanical studies of hydrogen-rich compounds. He contributed to the first discovery of hydride superconductors and single-molecule magnets.

His scientific accomplishments have been recognized through many national and international honours, including the Noranda Award of the Chemical Institute of Canada, Steacie Institute for Molecular Sciences Outstanding Achievement Awards, recognition as a STINT Fellow, Sweden, James M. Flaherty Visiting Professor, Ireland-Canada Foundation, election as a Fellow of the Royal Society of Canada, and appointment as a Distinguished Professor and Centennial Enhancement Chair of the University of Saskatchewan. More recently, he received the Inaugural Distinguished Alumni Award from the Faculty of Science of The Chinese University of Hong Kong.

举办单位：

竞彩足球比分-竞彩足球比分预测

物质模拟方法与软件教育部重点实验室