From water clusters to homogeneous catalysis: A savage journey to the heart of contemporary chemistry with a cryogenic photofragmentation mass spectrometer

Seminar | April 18 | 4-5 p.m. |  Pitzer Auditorium, 120 Latimer Hall

 Prof. Mark Johnson, Department of Chemistry, Yale University and Miller Visiting Professor, UC Berkeley

 College of Chemistry

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 vibrational spectroscopy. Advances in non-linear optics over the past decade allow single-investigator, table top laser access to IR bands from 550 to 4000 cm-1, essentially covering the same range as a typical FTIR instrument. When vibrational spectra are acquired using predissociation of weakly bound rare gas “tags,” the resulting spectra are equivalent to absorption spectra and correspond to target ions at a temperature of 10K. Taken together, what emerges is a new way to add a structural component to 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 everything from H-bonded water networks to the contact points between the constituents of ionic liquids. I will focus on whatever seems most interesting at the time!

 Light refreshments at The Coffee Lab at 3:50pm

 seminarcoordinator-cchem@berkeley.edu, 510-643-0572