21st Annual Stauffer Lectureship (Day 1 of 2): Professor Mark Johnson, Yale University
About the Seminar:
Mass spec meets FTIR: The genesis and promise of cryogenic ion vibrational spectroscopy (CIVP)
The coupling between ambient ionization sources, developed for mass spectrometric analysis of biomolecules, and cryogenic ion processing, originally designed to study interstellar chemistry, creates a new and general way to capture transient chemical species and elucidate their structures with optical spectroscopies. Advances in non-linear optics over the past decade allow single-investigator, table top lasers to access radiation from 550 cm-1 in the infrared to the vacuum ultraviolet. When spectra are acquired using predissociation of weakly bound rare gas “tags,” the resulting patterns are equivalent to absorption spectra and correspond to target ions at temperatures below 10K. Taken together, what emerges is a new and powerful structural component to traditional mass spectrometric analysis. Moreover, because the spectral features of the cold ions are sharp, the evolution of bond-specific transitions can be used to follow the docking arrangements of host-guest complexes and the local contact points between the ionic constituents of ionic liquids. Recent applications ranging from the mechanisms of small molecule activation by homogeneous catalysts to the structures of drug metabolites will be highlighted to emphasize the generality and utility of the methods in contemporary chemistry.
About Mark Johnson:
Mark Johnson is the Arthur T. Kemp Professor in the Department of Chemistry at Yale University. Johnson is known for the development and exploitation of experimental methods that capture and structurally characterize transient chemical species such as reaction intermediates. Most important among these is his exploitation of cryogenic ion chemistry in conjunction with multiple resonance laser spectroscopy. Johnson was born in Oakland, California in 1954 and raised in the San Francisco Bay Area. He graduated from the University of California at Berkeley with a degree in chemistry and a first exposure to fundamental research under the mentorship of C. Bradley Moore. He then earned his Ph.D. from Stanford University in 1983 under the guidance of Dick Zare, which involved an extensive collaboration with Joëlle Rostas at the Université de Paris-Süd. He was a postdoctoral fellow with Carl Lineberger at JILA/University of Colorado, Boulder from 1983-1985 and joined the Yale faculty in 1985. He rose rapidly through the ranks and has held the Kemp Professorship since 2006. He has served as Chair of APS Division of Laser Science and the ACS Division of Physical Chemistry, and is presently co-editor of the Annual Review of Physical Chemistry. He has been elected to Chair three Gordon Research Conferences- Molecular and Ionic Clusters (1996), Photoions (2001), and Gaseous Ions: Structures and Energetics (2015)).
Mark Johnson’s laboratory specializes in understanding chemical processes that occur in condensed phases by extracting key species directly from solution, freezing them into well-defined geometries in the gas phase, and then characterizing the potential energy surfaces that govern their reactivity through precision spectroscopic measurements. This endeavor requires the design and construction of new types of instrumentation that draw inspiration equally from analytical chemistry and atomic physics. From this effort has evolved a powerful new class of spectrometers that effectively bring an FTIR-like capability to mass spectrometry. These methods have provided microscopic pictures of how elementary species like protons and electrons are accommodated by water networks, as well as enabled capture of key reaction intermediates in both bio-inspired and organometallic catalysis. Although much of his work focuses on the properties of ions, he has also introduced variations that enable composition and size-selective measurements to be carried out on electrically neutral systems, with a notable application to homogeneous water clusters.
Professor Johnson’s accomplishments in teaching and research have been acknowledged by many awards and distinguished lectureships over the years, including the Yale College Dylan Hixon Award for Teaching Excellence in the Natural Sciences in 2007. He is a fellow of the American Physical Society (1999), the American Chemical Society (2012), the American Association for the Advancement of Science (2006) and the American Academy of Arts and Sciences (2009). He has given the Watkins Lectures at Wichita State University, the Pittcon Lectures at Duquesne University, the Condon Lecture at the University of Colorado, Boulder, the Reilly Lectures at Notre Dame, and the McElvain Lecture at the University of Wisconsin, Madison to highlight a few of the many presentations he has given to chemistry departments around the world. At the national level, he has received the APS Plyler Award for Molecular Spectroscopy (2006), the ACS Langmuir Award in Chemical Physics (2014), the Humboldt Senior Research Award (2012), the Miller Research Professorship (Berkeley, 2017), and was elected to the National Academy of Sciences in 2014.
These seminar is free and open to the public. All Stanford University Chemistry students are encouraged to attend this special event.
Questions: Please contact: chemistry-events [at] stanford.edu (chemistry-events[at]stanford[dot]edu)