Department of Chemistry & Biochemistry

Biography

2003-present

Notre Dame Radiation Lab

1985-2003

Argonne National Lab

1982

Ph.D., Northwestern University

1977

B.A., Hope College

Research Interests

Fast Kinetics of Free Radical Reactions — Free radicals are generated in virtually all radiation-initiated processes, and are responsible for most of the permanent chemical changes. The recombination reactions are often diffusion limited or nearly so, but also depend on pairing of spin to produce stable singlet products. This gives rise to the fascinating Chemically Induced Dynamic Electron Polarization (CIDEP) phenomenon in their time-resolved EPR spectra, and Chemically Induced Dynamic Nuclear Polarization (CIDNP) in NMR spectra of the recombination products, where some lines appear with negative phase due to population inversions.

Radiation Chemistry and Photochemistry of Water — To ionize water molecules in the gas phase requires at least 12.6 eV of energy, but dissociation of water to produce (H⁺)_aq, (e^-)_aq, and OH radicals can be accomplished in liquid water with 6 eV photons in a photochemical event that is still not well understood. What is the nature of electronically excited liquid water, and how can we explain the escape yields of H atoms, OH radicals, and solvated electrons?

Solvent Effects on Reaction Rates in Supercritical Water — Supercritical water is proposed as the coolant for efficient Generation-IV nuclear reactors, and is the medium for an important advanced oxidation technology for hazardous waste destruction. The properties of water change dramatically in the supercritical region as the water density changes continuously between zero and 1 g/cc. The primary free radicals in water – hydrated electrons, H atoms, and OH radicals – are respectively ionic, hydrophobic, and dipolar, providing opportunity to investigate nearly all possible solvent effects using radiolysis excitation. Many strange effects are being found, such as rate constants that decrease as the temperature is raised.

Recent Publications

• Elg, D. T.; Delgado, H. E.; Martin, D. C.; Sankaran, R. M.; Rumbach, P.; Bartels, D. M. and Go, D. B. "Recent Advances in Understanding the Role of Solvated Electrons at the Plasma-Liquid Interface of Solution-Based Gas Discharges" 2021 Spectrochimica Acta Part B-Atomic Spectroscopy, 186, 106307. DOI: 10.1016/j.sab.2021.106307.
• Marin, T. W.; Janik, I.; Bartels, D. M. and Chipman, D. M. "Failure of Molecular Dynamics to Provide Appropriate Structures for Quantum Mechanical Description of the Aqueous Chloride Ion Charge-Transfer-to-Solvent Ultraviolet Spectrum" 2021 Physical Chemistry Chemical Physics, 23 (15), pp.9109-9120. DOI: 10.1039/d1cp00930c.
• Dietz, T. C.; Thompson, A.; Al-Sheikhly, M.; Sterniczuk, M. and Bartels, D. M. "H-2 Production in the B-10(N,Alpha)Li-7 Reaction in Water" 2021 Radiation Physics and Chemistry, 180, 109319. DOI: 10.1016/j.radphyschem.2020.109319.
• Martin, D. C.; Bartels, D. M.; Rumbach, P. and Go, D. B. "Experimental Confirmation of Solvated Electron Concentration and Penetration Scaling at a Plasma-Liquid Interface" 2021 Plasma Sources Science & Technology, 30 (3), 03LT01. DOI: 10.1088/1361-6595/abe11c.
• Wang, P.; Grdanovska, S.; Bartels, D. M. and Was, G. S. "Corrosion Behavior of Ferritic FeCrAl Alloys in Simulated BWR Normal Water Chemistry" 2021 Journal of Nuclear Materials, 545, 152744. DOI: 10.1016/j.jnucmat.2020.152744.
• Delgado, H. E.; Brown, G. H.; Bartels, D. M.; Rumbach, P. and Go, D. B. "The Scaling of Kinetic and Transport Behaviors in the Solution-Phase Chemistry of a Plasma-Liquid Interface" 2021 Journal of Applied Physics, 129 (8), 083303. DOI: 10.1063/5.0040163.