Engineering Research Seminar Series 6, 2011: Dominance of Broken Bond and Nonbonding Electrons at the Nanoscale

Assoc. Prof. Dr Sun Chang Qing, School of Electrical & Electronic Engineering, Nanyang Technological University

Date: 2011-03-14
Time: 10:00 to 11:00
Venue: 5-4-22


Although they exist ubiquitously in our daily activities, the significance the nonbonding states, such as broken bonds, nonbonding lone pair and unpaired electrons, and anti-bonding dipoles, are often overlooked in practice. Recent research revealed that the presence of these nonbonding states and the associated energetics dominate the fascinating behavior of low-dimensional functional materials including biologic and organic species.

It is the hope that this presentation will help increase the awareness of the importance of the nonbonding electrons and the impact of the broken-bond-induced local bond contraction, quantum entrapment, and polarization of the nonbonding lone-electrons associated with atomic under-coordination at sites surrounding atomic vacancies, defects, surfaces, nanostructures of various shapes. Typical applications in the nanostructure functional materials design and extraction of quantitative information regarding the bond and electronic dynamics will be demonstrated. At the same time, an emphasis is also placed on the essentiality of interpreting the macroscopic properties of a material from the perspective of bond and nonbond formation, dissociation, relaxation and vibration, and the associated energetics and dynamics of charge repopulation, polarization, densification and localization.

About the Speaker

Chang Q Sun, FRSC, FInstP, received a PhD in 1996 at Murdoch University, Australia. With research interest in surface, interface, and low-dimensional Physics and Chemistry, CQ Sun has been focusing on the theme of “Coordination bond-and-band engineering” since earlier 1990’s with the development of a sequential theories and theory-enabled techniques including STM/VLEED quantification of four-stage Cu3O2 bonding kinetics and atomic-scaled photoelectron spectroscopic purification of bond and electronic information in selected zones. Achievements have been documented in over 240 journal articles including a number of thematic reports with over 2800 citations.