Jay A. LaVerne Lamar University, B.S. ('72) University of Nebraska, Ph.D. ('81) Tel. (574) 631-5563 e-mail: laverne.1@nd.edu Radiation Chemical Effects with Heavy Ions

Scientific Interests

Experimental heavy ion studies —determination of product yields in the radiolysis of water, aqueous solutions, liquid hydrocarbons, polymers, and DNA with particles ranging from protons to uranium ions.

Physical track structure — theoretical description of the physical characteristics of particle tracks in liquids.

Track chemistry — diffusion-kinetic modeling of the nonhomogeneous spatial distributions of the transient species produced by the absorption of energy by ionizing radiation.

Interfaces — elucidation of the radiation chemical effects occurring at the interface of ceramic oxides and water.

Recent Accomplishments | Top |

Radiolysis of Ceramic Oxide – Water Interfaces —Diffuse Reflection Infrared Fourier Transform (DRIFT) spectroscopy shows that H2O2 forms an adduct on the oxide surfaces of ZrO2 and TiO2. This adduct was found to decay with the concurrent formation of O2 in the case of TiO2. Raman scattering and EPR techniques were unable to conclusively identify specific species on the surface. H atoms are observed at 77 K using EPR, but it could not be determined if these species were on the surface or in the bulk. A device for the in situ radiolysis and DRIFT analysis of oxides is currently under construction for a more controlled examination of oxide surfaces.

Degradation of Polymers — Radiolysis studies on the decomposition of PVC in association with water have focused on the post-radiolytic decay of products. EPR spectroscopy revealed the decay of a radical species within about 24 hours leaving another very long lived radical that was stable for days. Radiolysis under controlled atmospheres suggests that the shorter lived radical decays by diffusion of O2 into the bulk polymer. The production of HCl seems to have a similar dependence on O2. Further work will examine radiolytic decay of the polymeric backbone and the effects of additives.

H Atom Formation in Water —Experimental measurements of molecular hydrogen including the use of isotopic techniques were combined with track model calculations to determine H atom yields in the radiolysis of water. H atoms yields determined by subtraction of total molecular hydrogen production in neat water from that observed in formate solutions is found to agree well with the more direct measurement of HD using deuterated formate as a scavenger. H atoms yields are found to decrease with the evolution of the radiation track and decrease with increasing LET.

State Selected Decomposition of Liquid Aromatics —Photochemical studies of aromatic compounds useing specific excitation wavelengths show that the production of H2 from benzene, toluene, pyridine, and aniline is negligible at wavelengths above 214 nm (below 5.8 eV) corresponding to the lowest energy levels of these compounds. At 185 nm (6.7 eV) H2 production is significant for all of these compounds suggesting that H2 is produced almost exclusively by decay of highly excited states.

Selected Publications | Top |

K. Enomoto, J.A. LaVerne, L. Tandon, A.E. Enriquez and J.H. Matonic
The radiolysis of poly(4-vinylpyridine) quaternary salt ion exchange resins
J. Nucl. Mater. 2008 373, 103-11 link

K. Enomoto and J.A. LaVerne
Reactions of hydrated electrons with pyridinium salts in aqueous solutions
J. Phys. Chem. A 2008 112, 12430-6 link

M. Huerta Parajon, P. Rajesh, T. Mu, S.M. Pimblott and J.A. LaVerne
H atom yields in the radiolysis of water
Radiat. Phys. Chem. 2008 77, 1203-7 link

J.A. LaVerne, E.A. Carrasco-Flores, M.S. Araos and S.M. Pimblott
Gas production in the radiolysis of poly(vinyl chloride)
J. Phys. Chem. A 2008 112, 3345-51 link

K. Enomoto, J.A. LaVerne and M.S. Araos
Heavy ion radiolysis of liquid pyridine
J. Phys. Chem. A 2007 111, 9-15 link

Carrasco-Flores E. A. and J. A. LaVerne
Surface species produced in the radiolysis of zirconia nanoparticles
J. Chem. Phys. 2007 127, 234703 link

Supported by the Division of
Chemical Sciences
Office of
Basic Energy Sciences
at the
U.S. Department of Energy

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Last Modified: 02/26/2009