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 —Modifications to water – zirconia nanoparticle interfaces induced by g-irradiation have been examined using diffuse reflection Fourier transformer-infrared (DRIFT), Raman scattering, and electron paramagnetic resonance (EPR) techniques. DRIFT spectra show that the bridged Zr – OH – Zr species decreases relative to the terminal Zr – OH species upon irradiation. No variation is observed with Raman scattering, indicating that the zirconia morphology is unchanged. EPR measurements suggest the possible formation of the superoxide ion, presumably by modification of the surface OH groups. Trapped electrons and interstitial H atoms are also observed by EPR.

Water Excited State Decomposition — Direct observation of the fluorescence from liquid benzene has given, for the first time, the temporal variation of excited states in a neat liquid irradiated with heavy particles. The yields of excited states are found to decrease with increasing particle linear energy transfer, LET, because of intratrack quenching.

Radiolytic Decomposition of Pyridine —A pulse radiolysis study of the formation and decay of the triplet excited state of liquid pyridine shows that it has a first-order decay with a lifetime of 72 ns and a yield of 1.3 molecules/100 eV. This value is very similar to the previously determined yield of 1.25 molecules/100 eV for dipyridyl and scavenger studies suggest the two are related. A pyridyl radical – pyridine (dimer) complex is detected at l = 390 nm, and is consistent with iodine scavenging effects. Formation of the pyridiniumyl radical cation – pyridine charge transfer complex is proposed to be insignificant in liquid pyridine.

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

P. Rajesh, J.A. LaVerne and S.M. Pimblott
High dose radiolysis of aqueous solutions of chloromethanes: Importance in the storage of radioactive organic wastes
J. Nucl. Mater. 2007 361, 10-7 link

S.M. Pimblott and J.A. LaVerne
Production of low-energy electrons by ionizing radiation
Radiat. Phys. Chem. 2007 76, 1244-7 link

J.A. LaVerne, K. Enomoto and M.S. Araos
Radical yields in the radiolysis of cyclic compounds
Radiat. Phys. Chem. 2007 76, 1272-4 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: 05/05/2008