1999 M. T. Thomas Award
Wang Recognized for Outstanding Postdoctoral Achievement
Dr. Xuebin Wang
Dr. Xuebin Wang has been selected as the 1999 recipient of the M. T. Thomas Award for Outstanding Postdoctoral Achievement.
Dr. Wang was selected for his phenomenal scientific accomplishments and productivity. He is specifically recognized for his major contributions to the design and construction of a new experimental apparatus to investigate multiply charged anions, his subsequent series of outstanding discoveries using this newly developed apparatus, and his penetrating insight in interpreting and understanding the experimental results.
Although multiply charged anions are common in the condensed phase and have been taken for granted in the teaching of chemistry, very few of these species have been observed as free molecular entities in the gas phase prior to the research of Dr. Wang. Working in the group of Prof. Lai-Sheng Wang (no relation), he helped design and build the first of its kind experimental apparatus to investigate gaseous multiply charged anions using electrospray and photodetachment photoelectron spectroscopy [Wang, Ding, Wang, and Barlow, Rev. Sci. Instrum. 70, 1957 (1999)]. This experimental technique opens a whole new realm of investigation, in the gas phase, of not only multiply charged anions but also many other solution phase phenomena, such as solvation effects, H-bonding, and electron transfer reactions.
Using this unique experimental capability, Dr. Wang has obtained a series of outstanding research results. His initial experiments led to the first direct observation of a repulsive Coulomb barrier that exists universally in any free multiply charged anions [Wang, Ding, and Wang, Phys. Rev. Lett. 81, 3351 (1998).] He subsequently measured the magnitude of the repulsive Coulomb barriers in a series of aliphatic dicarboxylate dianions and determined the relationship between the repulsive Coulomb barrier and the intramolecular Coulomb repulsion due to the excess charges [Wang, Ding, Wang, and Nicholas, Phys. Rev. Lett. 81, 2667 (1998)]. He was also the first to observe electron tunneling through the repulsive Coulomb barriers and quantitatively interpreted the tunneling phenomenon using the theory of a-decay [Wang, Ding, and Wang, Chem. Phys. Lett. 307, 391 (1999)].
Dr. Wang's recent work demonstrated that the repulsive Coulomb barrier can make electronically unstable multiply charged anions sufficiently long-lived to be observed experimentally. His experiment resulted in the remarkable observation of negative electron binding energy in a long-lived, electronically metastable molecule for the first time [Wang and Wang, Nature 400, 245 (1999)]. Such molecules store purely electrostatic energies (without bond breaking) and can be viewed as molecular capacitors. This work was featured in the Science and Technology Concentrate section of Chemical and Engineering News (July 19, 1999). A full report of this research will appear in the January 13 (2000) issue of J. Phys. Chem. A (Wang, Ferris, and Wang) and will be featured on the cover of that issue.
The smallest molecular entity that can support two or more excess negative charges is still an open question in chemical physics. Dr. Wang's most recent work has led to the observation of the smallest doubly charged anions consisting of only five atoms, that have yet been observed in a solvent-free environment [Wang and Wang, Phys. Rev. Lett. 83, 3402 (1999)]. This result has provided significant insight into the electronic vs. thermodynamic stability of multiply charged anions. Dr. Wang has also obtained significant results of redox species in the gas phase, providing a new experimental method to determine the reorganization energies and energetics of electron transfer reactions.
Dr. Wang obtained his B.S. degree in Chemical Physics from the University of Science and Technology, People's Republic of China, and his M.S. and Ph.D. degrees in Chemical Physics from the Institute of Chemistry, Academia Sinica, People's Republic of China. He joined the EMSL's Chemical Structure and Dynamics program as a postdoctoral fellow in February 1997, working with Prof. Lai-Sheng Wang.
The award will be presented to Dr. Wang at 3:30pm, February 10, 2000, in the EMSL auditorium. Dr. Wang will give a presentation entitled "Probing Multiply-Charged Anions in the Gas Phase Using Photodetachment Photoelectron Spectroscopy." A reception will be held following the presentation.
