Professor Mark Thiemens
University of California - San Diego
October 5^th through 7^th, 2009

Mark Thiemens is Professor of Chemistry and Biochemistry at the University of California - San Diego. He has also served as Dean of Physical Sciences at UCSD since Fall 2000. The recipient of a doctoral degree in chemical oceanography from Florida State University, Thiemens arrived at UCSD in 1980, after a three-year postdoctoral fellowship at the Enrico Fermi Institute for Nuclear Studies at the University of Chicago. As a scientist, he is best known for his discovery of the "mass-independent isotope effect," which has improved scientific understanding in areas as diverse as climate change, the origin of the solar system, chemical physics, acid rain, and the accumulation of greenhouse gases. The discovery led to his selection for the 1998 Ernest O. Lawrence Medal, the most prestigious award given to scientists by the U.S. Department of Energy. Professor Thiemens and his research group have developed the analytical capability to measure stable isotope variations at ultra-high precision (0.04 parts per thousand) in sulfur (³⁴S/³⁴S, ³³S/³²S), oxygen (¹⁸O/¹⁶O, ¹⁷O/¹⁶O), carbon (¹³C/¹²C), and nitrogen (¹⁵N/¹⁴N). He and his group have collected and analyzed samples throughout the world and include measurements at the South Pole and in tropical rainforests. Professor Thiemens was elected to the National Academy of Sciences in 2006, one of the highest honors bestowed on U.S. scientists and engineers. In addition to his many honors and awards, a minor planet orbiting the inner part of the main asteroid belt was designated (7004) Markthiemens in honor of his work in 2006.