21st Annual Stauffer Lectureship (Day 2 of 2): Professor Mark Johnson, Yale University

About the Seminar:

Grotthuss redux: Decoding the spectroscopic signatures of mobile protons in H-bonded networks

The Grotthuss “proton relay” mechanism explains the anomalously high proton mobility in water as a sequence of proton transfers along a hydrogen bonded network.  Although the vibrational spectroscopic signatures of this process are masked by the diffuse nature of the key bands in bulk water, we discuss how the much simpler spectra of cold, composition-selected heavy water clusters, D+∙(D2O)n, can be exploited to capture clear markers that track the course of the fundamental proton transfer event.  The extreme variations in these frequencies are traced to the remarkable polarizability of the H5O2+ ion, first identified by Georg Zundel almost 50 years ago.

About the Speaker:

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.