PChem Seminar – Dr. Herman Cho, PNNL
About the event
Speaker: Dr. Herman Cho, Pacific Northwest National Laboratory
Host: Dr. Ivan Popov
Title: Solid State Magnetic Resonance Spectroscopy of Actinide Systems: The Why and How
The distinctive ability of actinide elements to interact with ligands through both covalent and ionic bonds has proven challenging to reconcile with fundamental concepts of electronic structure derived from experience with lighter elements. The deviation of the actinide row from conventional f-block behavior has drawn the attention of researchers since the discovery of the transuranic elements and continues to confound attempts to predict and control the properties of these elements in contexts ranging from nuclear fuel research, radioactive waste management, environmental remediation, and national security. At the Pacific Northwest National Laboratory, we seek to elucidate chemical bonding in actinide clusters through studies of solids that allow substitution of different elements into complexes with identical or nearly identical molecular structures. Anisotropic interactions in these systems measured by magnetic resonance, such as quadrupolar couplings, magnetic shieldings, and hyperfine shifts, are among the most informative and sensitive parameters available for determination of electronic structure. Experiments on radioactive actinide complexes present unique difficulties, and have required both theoretical and technical advances for implementation and interpretation.
Bio: Herman Cho is Senior Research Scientist in the Physical and Computational Sciences Directorate at the Pacific Northwest National Laboratory where he is the principal investigator of the U.S. DOE Basic Energy Sciences Heavy Element Chemistry program. He has led the development of a radiological magnetic resonance spectroscopy facility at PNNL that has reported multiple first-in-the-world advances in the analysis of highly radioactive materials.
Before joining the Pacific Northwest National Laboratory, Dr. Cho was a Bantrell Research Fellow at the California Institute of Technology and a Postdoctoral Fellow of the U.S. National Science Foundation with Profs. Richard R. Ernst and Arthur Schweiger at the ETH in Zürich, Switzerland.His Ph.D. in chemistry is from the University of California, Berkeley, where he was a student with Prof. Alexander Pines.