Richard Field
Professor
Email: richard.field@umontana.edu
Phone: (406) 243-6374
Lab: (406) 243-4163
Dick Field came to UM in 1975 from Carnegie-Mellon University. He received his Ph.D. degree in 1968 from the University of Rhode Island and carried out postdoctoral research with R.M. Noyes at the University of Oregon. He has served as visiting professor at the University of Oregon, the University of Notre Dame, The University of Würzburg, Germany, and as visiting scientist at the National Center for Atmospheric Research. Dick is a physical chemist specializing in the kinetics of oscillating reactions and atmospheric chemistry. He teaches undergraduate and graduate courses in physical chemistry.
Research Interests
The mechanism of a complex chemical transformation is the collection of simple, one-collision chemical reactions
(among the reactant, product, and intermediate species making up the reacting chemical system) that acting together cause an observed net chemical change. Our research has focused for over thirty years upon such mechanisms and the often nonlinear sets of differential equations governing their temporal and spatial evolution in a far-from-equilibrium circumstance.
This work has both experimental and theoretical components. Of particular interest to us are reactions exhibiting complex temporal and spatial behaviors in the concentrations of chemical species that spring from a nonlinear governing dynamic law. Such behaviors include multiple steady states, steady-state instability leading to oscillation, excitability, traveling waves, quasiperiodicity, and chaos, as well as complexity resulting from the bifurcation structure associated with transitions among these various behaviors.
Our work was until recently directed mainly toward achieving fundamental understanding of classic oscillating
chemical reactions. The major of these classic systems is the Belousov-Zhabotinsky (BZ) reaction, which
exhibits under suitable conditions all of the above complex behaviors. The BZ reaction is the metal-ion
[e.g., Ce(IV)/Ce(III) or Fe(phen)33+ /Fe(phen)32+] catalyzed oxidation of organic substrates [e.g., CH2(COOH)2]
by BrO3. However, while we continue this work, our interests over the last decade have expanded into application of methods and insights developed in these classic systems to similar nonlinear behavior in atmospheric chemistry and even climate dynamics.
Our atmospheric chemistry work has developed in two major directions. (1) Investigation of small models of tropospheric photochemistry intended to understand its underlying dynamic structure. (2) Simulations using large, detailed mechanisms of the photochemistry occurring in biomass-burning smoke plumes intended to both understand their chemical dynamics and to make useful predictions of the effect of such emissions upon regional and global atmospheres.
Small model work (1) has helped demonstrate the basic nonlinear nature of tropospheric photochemistry. For example, under some circumstances an increase in [NOx] leads to an increase on [O3], while under other circumstances a increase in [NOx] may lead instead to a decrease in [O3]. This phenomenon results from the existence of high- and low-[NOx] tropospheric processing states of quite different chemical properties. Excitability, oscillation and even chaotic behavior of the concentrations of O3 and other species present in the troposphere have been observed in these small models and demonstrate the basic dynamic instability of tropospheric photochemistry. These phenomena are related to existence of the above high- and low-[NOx] processing states, and the coupling of these states via positive and negative feedback loops. Current small-model work involves investigation of meteorological coupling of several well-mixed air packets undergoing tropospheric photochemistry, as well as perturbation effects on such cells, including stochastic resonance and induced chaotic behavior.
Simulation of the photochemistry and dilution effects leading to the spatial and temporal evolution of forest-fire smoke-plume chemical composition (2) is done in collaboration with Professor Robert J. Yokelson, of the UM Department of Chemistry and the USDA Forest Service, Fire Sciences Laboratory in Missoula, who carries out field measurements on smoke plumes using airborne FT-IR spectroscopy. Recent accomplishments include assessment of the effect upon smoke plume photochemistry of oxygenated species (e.g., H2CO, CH3OH, HOCHO, and phenol) recently found by Professor Yokelson to be directly emitted in significant quantities by biomass combustion, and prediction of the effect upon the concentrations of O3 (as well as secondary pollutants such as PANs and hydroperoxides) of the mixing of an NOx-poor (volatile organics rich) smoke plume with a NOx-rich (volatile organics poor) urban air mass.
Current work in this area involves the effect of cloud-processing on the chemistry of smoke plumes (based upon observations by Professor Yokelson during SAFARI-2000 campaign) using models developed in our previous work, as well as the systematic reduction of these very large mechanisms to smaller, less computationally expensive models that accurately reproduce the results obtained with very large models. This work contributes to both our understanding of the basic chemistry and physics of biomass-burning smoke plumes and to the development of public policy concerning management of controlled and wild biomass burning.
Our work has been supported by the National Science Foundation (NSF) and by the National Aeronautics and Space Administration (NASA).
Professor Field became Emeritus in May, 2005, and is not taking on new research students. However, he expects to continue to teach physical chemistry and to be available for informal collaborations.
Course Links
Chemistry 371 Past Exams 2005
Chemistry 371 Past Exams 2006
Chemistry 371 Past Quizzes 2006
Chemistry 371 Syllabus 2007
Chemistry 371 Autumn Exams 2007
Chemistry 372 Past Exams 2004
Chemistry 372 Past Exams 2005
Chemistry 372 Past Exams 2006
Representative Publications
An NMR Study of the Equilibration of d-Glucaric Acid with Lactone Forms in Acueous Acid Solutions, J.M. Brown, M. Manley-Harris, R.J. Field, D.E. Kiely. Journal of Carbohydrate Chemistry, 26, 1-13 (2007).
Activation Energy for disproportionation of HBrO and Estimated Heats of Formation of HBrO2 adn BrO2, Jesús Alberto Agreda B. and Richard J. Field, J. Phys. Chem. A, 110 (25) 7867-7873 (2006).
Oxidation State of BZ Reaction Mixtures, Sabrina G. Sobel, Harold M. Hastings, and Richard J. Field, Journal of Physical Chemistry, 110, 5- 7 (2006).
Microscopic fluctuations and pattern formation in a supercritical oscillatory chemical system, Harold M. Hastings, Richard J. Field and Sabrina G. Sobel. J. Chem. Physics, 119, 3291-3296 (2003).
Steady State Instability and Oscillation in Simplified Models of Tropospheric Chemistry, Mark R. Tinsley and Richard J. Field. J. Phys. Chem. A, 105,11212-11219 (2001).
Characterization of Oscillation and a Period-Doubling Transition to Chaos Reflecting Dynamic Instability in a Simplified Model of Tropospheric Chemistry, R.J. Field, P. G. Hess, L. V. Kalachev, and S. Madronich, J. Geophys. Res., 106D, 7553-7565 (2001).
Kinetic Evidence for Accumulation of Stoichiometrically Significant Amounts of H2I2O3 in the Reaction of I! with HIO3, Jesus Agreda, Nancy J. Lyons, and Richard J. Field, J. Phys Chem., 104, 5269-5274 (2000).
Department of Chemistry The University of Montana Missoula, MT 59812 (406) 243-4022 Fax: (406) 243-4227
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