Sandia National Laboratories, California P.O. Box 969 Livermore, CA 94551-0969
Biography
Tim Zwier joined Sandia National Laboratories’ Combustion Research Facility (CRF) in January 2020 after spending much of his independent research career in academia. Zwier had served as PhD research advisor for more than 40 graduate students and about a dozen post-doctoral research associates. His research interests span the areas of large-molecule spectroscopy and chemical dynamics. With other Gas Phase Chemical Physics program (GPCP) staff at Sandia, he is developing and using modern tools of gas-phase chemical physics to probe the spectroscopy and dynamics of molecules that can undergo conformational isomerization, structural isomerization, and/or chemical reaction on complex potential energy surfaces.
Current Research
We prepare and study molecules under state-resolved conditions to gain insight to their structures, relative energies, interconversion, and reaction at the highest levels of detail and quantitative accuracy. Double resonance measurements involving microwave, infrared, and ultraviolet spectra of individual isomers serve as a foundation for pump-probe experiments following selective electronic or infrared excitation of individual isomers.
Studies of the infrared and ultraviolet spectroscopy of large molecular ions and complexes are carried out in a versatile, multi-stage mass spectrometer shown in Figure 1 that incorporates a cryo-cooled ion trap. Single-conformation IR and UV spectra are recorded using IR-UV double resonance photofragment spectroscopy.
Figure 1: Multi-stage Mass Spectrometer used to study the infrared and ultraviolet spectroscopy and photochemistry of cryo-cooled, gas-phase ions.
Our research group also uses a broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer (Figure 2) outfitted for photoionization time-of-flight mass spectrometry (TOFMS). The TOFMS is used to optimize conditions for production of specific reactive intermediates before recording broadband microwave spectra over the 2-18 GHz range under those conditions. We are also developing a cryo-cooled buffer gas cell as an alternative means of studying reactive intermediates.
Figure 2a: Photograph of the vacuum chamber and associated electronics used to record broadband rotational spectra and VUV photoionization TOF mass spectra.
Figure 2b: Schematic diagram of the microwave electronics used to record broadband rotational spectra.
Research Interests
Gas phase molecular spectroscopy, chemical dynamics, conformational isomerization, multi-chromophore molecules, excited state spectroscopy and photochemistry, structural characterization of free radicals and reactive intermediates, studies of ions in molecular cavities, and atmospheric sulfur oxidation chemistry. Google Scholar
Professional Organizations & Leadership
Purdue University
M.G. Mellon Distinguished Professor of Chemistry: 2007 to 2018
Department Head, Department of Chemistry: 2013 to 2017
Department Head, Department of Chemistry: 2004 to 2008
Professor of Chemistry: 1997 to 2006
Assistant, Associate Professor of Chemistry: 1988 to 1997
Calvin College
Assistant Professor of Chemistry: 1983 to 1988
The Journal of Physical Chemistry Letters
Senior Editor: 2010 to 2019
The Journal of Physical Chemistry
Senior Editor: 2003 to 2009
Awards
Award
Year
Humboldt Research Award, Alexander von Humboldt Foundation
2017
American Association for the Advancement of Science Fellow
2016
Arthur E. Kelly Award for Outstanding Teaching
2014
American Chemical Society Fellow
2010
Earle K. Plyler Prize in Molecular Spectroscopy, APS
