J. Hodge Markgraf Professor of Chemistry, Emeritus
413-597-2280
At Williams since 1988
Areas of Expertise
Vibrational Overtone Spectroscopy of HFCs
Hydrofluorocarbons (HFCs) are being commercially developed as alternatives for the stratospheric-ozone-depleting chlorofluorocarbons (CFCs) and halons. I’m interested in the dynamics of these molecules when they have chemically significant amounts of internal energy, i.e. when they are near to dissociation. My students and I investigate the CH vibrational overtone spectroscopy of these molecules. Since these transitions are quite weak, we employ the sensitive experimental technique of cavity ringdown spectroscopy for detection and measurement of absolute absorption cross-sections. For help in interpreting the spectra, we perform density functional and ab initio molecular electronic structure calculations (with Prof. H. Kjaergaard, U. Otago, Dunedin, New Zealand) to model the highly vibrationally excited behavior.
Environmental Chemistry
The local environment provides many chemical research opportunities. Using the resources of the Environmental Analysis Laboratory on campus, I have collaborated on projects including studies of: lead in urban soils intended for community gardens, perchlorate ions in drinking water at the local high school, PCBs in the Hoosic River, and heavy metals in fish taken from local ponds.
Scholarship/Creative Work
- “The Importance of Oxbow Lakes to the Floodplain Storage of Pollutants”, Summer-Solstice Thomas, José Antonio Constantine, David Dethier, John W. Thoman Jr., Jason Racela, Emmett Blau, and Joshua D. Landis, Geology, 50, 392-396 (2022).
- Raymond Chang and John W. Thoman, Jr., Physical Chemistry for the Chemical Science (University Science Books, Mill Valley, CA 2014).
- “Evidence for a blue-shifting intramolecular hydrogen bond in the vibrational overtone spectrum of 1H-nonafluorobutane,” Brian G. Saar, Geoff P. O’Donoghue, Adam H. Steeves, and John W. Thoman, Jr., Chem. Phys. Letts. , 417, 159-163 (2006).
- “CH-Stretching Oertone Spectroscopy of 1,1,1,2-Tetrafuoroethane,” Brian G. Saar, Adam H. Steeves, John W. Thoman, Jr., Daryl L. Howard, Daniel P. Schofield, and Henrik G. Kjaergaard, J. Phys. Chem. A., 104, 5323-5331 (2005).
- “Illustrating Chemical Concepts with Coin Flipping,” R. Chang and J. W. Thoman, Jr., Chem. Educator, 6, 1-2 (2001).
- “Absolute CH radical concentrations in rich low-pressure methane-oxygen-argon flames via cavity ringdown spectroscopy of the A doublet Delta – X doublet Pi transition,” John W. Thoman, Jr. and Andrew McIlroy, J. Phys. Chem. A., 4953-4961 (2000).
- “Adiabatic Ionization Potential and electron affinity of formaldehyde,” Joseph S. Francisco and John W. Thoman, Jr., Chem. Phys. Letts. 300, 553 (1999).
- “Collisional electronic quenching rates for NO A doublet Sigma + (v’=0),” P.H. Paul, J.A. Gray, J.L. Druant, Jr., and J.W. Thoman, Jr., Chem. Phys. Letts. 259, 508 (1996).
- “Collisional Quenching Corrections for Laser-Induced Fluorescence Measurements of NO A2 Sigma+,” P.H. Paul, J.A. Gray, J.L. Durant, Jr., and J.W. Thoman, Jr., AIAA Journal, 32, 1670 (1994).
- “Near-resonant electronic energy transfer in the electronic quenching of NO A2 Sigma+ by several fuel gases and ammonia,” M.R. Furlanetto, J.W. Thoman, Jr., J.A. Gray, J.L. Durant, Jr., and P.H. Paul, J. Chem. Phys., 101, 10452 (1994).
- “A Model for Temperature-Dependent Collisional Quenching of NO A2 Sigma+,” P.H. Paul, J.A. Gray, J.L. Durant, Jr., and J.W. Thoman, Jr., Appl. Phys. B 57, 249 (1993).
- “Collisional electronic quenching of NO A2 Sigma+ by N2 from 300 to 4500 K,” J.W. Thoman, Jr., J.A. Gray, J.L. Durant, Jr., and P.H. Paul, J. Chem. Phys. 98, 8156 (1992).
- “Photofragment Imaging: The 205-nm Photodissociation of CH3Br and CD3Br,” Wayne P. Hess, David W. Chandler, and John W. Thoman, Jr., Chem. Phys. 164, 277 (1992).
- “REMPI Spectroscopy of CF3I in Bulk and a Molecular Beam,” G. van den Hoek, D.W. Chandler, J.W. Thoman, Jr., and S. Stolte, Chem. Phys. Letts. 188, 413 (1992).
- “Photofragment Imaging: The 266-nm Photolysis of CD3I,” D.W. Chandler, M.H.M. Janssen, S. Stolte, R.N. Strickland, J.W. Thoman, Jr., and D.H. Parker, J. Phys. Chem. 94, 4839 (1990).
Previous Courses Taught
- CHEM/ARTS 16: Glass and Glassblowing (WSP 2024)
- CHEM 116: Chemistry and Physics of Cooking (Spring 2014)
- CHEM 151: Concepts of Chemistry (Fall 2008)
- CHEM 153: Concepts of Chemistry: Advanced Section (Fall 2018)
- CHEM 155: Principles of Modern Chemistry (Fall 2016)
- ENVI 102: Introduction to Environmental Science (Spring 2008)
- CHEM 256: Advanced Chemical Concepts (Spring 2021)
- CHEM 364: Instrumental Methods of Analysis (Spring 2004)
- CHEM 361: Physical Chemistry: Structure and Dynamics (Fall 2021)
- CHEM 366: Physical Chemistry: Thermodynamics (Spring 2018)
- CHEM 368T: Quantum Chemistry and Molecular Spectroscopy (Spring 2006)
Honors Students
|
|
Other Student Collaborators
|
|