Dr. Paul Marshall

Dr. Paul Marshall

Regents Professor of Chemistry
University of North Texas
Department of Chemistry
1155 Union Circle #305070
Denton, Texas 76203-5017
(940) 565-2294

My research interests include: Gas-phase kinetics of atoms and small molecules; atmospheric and combustion chemistry. Elementary reactions are studied over wide temperature ranges, and the results related to ab initio theoretical calculations.

My research lies in chemical kinetics and molecular dynamics, particularly the measurement and theoretical interpretation of rate coefficients for elementary gas-phase reactions, and combustion and environmental chemistry. Networks of reactions of atomic and molecular radicals control the chemistry of flames. They also control the chemistry of the atmosphere, as well as aspects of laser and interstellar chemistry and chemical vapor deposition.

Dr. Jessie Yuan

Dr. Jessie Yuan using the laser photolysis apparatus

A major part of the research involves the investigation of temperature dependences and the mechanisms of these processes. The outcome is a better understanding of reactivity and the details of chemical change in systems unaffected by solvent interactions.

The experiments involve spectroscopic monitoring of radicals at trace concentrations and over wide ranges of temperature (from ambient to flame conditions). Laser methods are employed with fast photo-electric detection to monitor reactions with microsecond time resolution. Large scale ab initio quantum calculations help to interpret the experimental results and are used to predict the properties of reactive intermediates and transition states.

Current research focuses on reactions of hydroxyl radicals, an important oxidizing species in both the environment and in flames, with pi bonded systems such as carbonyl compounds and ethylenes. Theoretical analysis of the potential energy surfaces gives insight into the unusual temperature dependences and non-Arrhenius behavior of these systems.

The atmospheric and combustion chemistry of sulfur compounds is a topic of continuing interest, together with studies of the reactivity and thermochemistry of transient silicon and metal-containing molecules.

Selected Publications:

"Kinetic Studies of the Cl + HI Reaction using Three Techniques", J. Yuan, A. Misra, A. Goumri, D.D. Shao and P. Marshall, J. Phys. Chem. A, 108, 6857 (2004).

"Reaction Kinetics of the Addition of Atomic Sulfur to Nitric Oxide", A. Goumri, D.D. Shao and P. Marshall, J. Chem. Phys., 121, 9999 (2004).

"Mechanism and Modeling of the Formation of Gaseous Alkali Sulfates", P. Glarborg and P. Marshall, Combust. Flame, 141, 22 (2005).

"A Computational Study of the Thermochemistry of Bromine and Iodine-Containing Methanes and Methyl Radicals", P. Marshall, G.N. Srinivas and M. Schwartz, J. Phys. Chem. A, 109, 6371 (2005).

"Modified Transition State Theory and Negative Apparent Activation Energies of Simple Metathesis Reactions: Application to the Reaction CH3 + HBr → CH4 + Br", L.N. Krasnoperov, J. Peng and P. Marshall, J. Phys. Chem. A, 110, 3110 (2006).

"Kinetics and Thermochemistry of the Addition of Atomic Chlorine to Acetylene", Y. Gao, I.M. Alecu, P.-C. Hsieh, A. McLeod, C. McLeod, M. Jones and P. Marshall, Proc. Combust. Inst., 31, 193 (2007).

"Kinetic Studies of Chlorobenzene Reactions with Hydrogen Atoms and Phenyl Radicals and the Thermochemistry of 1-Chlorocyclohexadienyl Radicals", Y. Gao and P. Marshall, Proc. Combust. Inst., 32, 351 (2009).

"Kinetic and Modeling Studies of the Reaction S + H2S" Y. Gao, C. Zhou, K. Sendt, B.S. Haynes and P. Marshall, Proc. Combust. Inst., 33, 459 (2011).

"Inhibition of Hydrogen Oxidation by HBr and Br2" G. Dixon-Lewis, P. Marshall, B.Ruscic, A. Burcat, E. Goos, A. Cuoci, A. Frassoldati, T. Faravelli and P. Glarborg, Combust. Flame, 159, 528 (2012).