Jay A. LaVerne
Lamar University, B.S. ('72)
University of Nebraska, Ph.D. ('81)
Tel. (574) 631-5563
Radiation Chemical Effects with
Experimental heavy ion studies
determination of product yields in the radiolysis of water, aqueous solutions, liquid hydrocarbons, polymers, resins, and ionic liquids with particles ranging from protons to uranium ions.
Condensed phase radiolysis
examine the main pathways for medium decomposition due to the passage of ionizing radiation.
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 nanoparticles and water including condensed ices.
Recent Accomplishments | Top |
Radiolysis of Ceramic Oxide – Water Interfaces —Modifications to water –nanoparticle interfaces induced by fast electron and g-irradiation have been examined using diffuse reflection infrared Fourier transform (DRIFT), Raman scattering, and electron paramagnetic resonance (EPR) techniques. Gas evolution studies show the transport of energy and charge through the interface is responsible for much of the observed radiation chemistry. These studies have identified the water layers near to, but not at, the interface for being the most radiation chemically active. Further studies are examining radiation effects following modification of the surfaces of a variety of ceramic oxides, including the iron oxides. Alpha particle radiolysis is being compared with the results found with conventional radiolysis.
Degradation of Polymers and Resins The radiolysis of resins and polymers used in the separation and storage of waste materials have received considerable interest because of their applications in the nuclear industry. Polymers such as PVC clearly show substantial post irradiation effects due to the decays of long lived radicals, which can lead to formation of the corrosive chloride anion. PVC is extensively used in waste storage following the Fukushima accident and long term radiation effects are of vital importance. The radiolytic decay of resins such as Reillex and Amberlite are very dependent on the amount of water present and various characteristics of the radiation. The production of H2 from these compounds is of considerable concern and the degradation of medium decay products seems to be of great importance.
Hydrogen Peroxide Formation and Decomposition in Water Hydrogen peroxide is one of the most important oxidizing species produced in the radiolysis of water with respect to radiation induced corrosion and yet the mechanism is only now becoming unraveled. Experiments have shown that H2O2 readily decays by first adsorbing on the surface of ceramic oxides with the production of OH radicals. The presence of added H2 or variation in pH can affect the overall rate of H2O2 decomposition by methods not yet understood. Efforts are currently underway to map the radiolytic response to a variety of ceramic oxides for both fundamental information and for applications in waste storage.
State Selected Decomposition of Liquid Aromatics The radiolytic response of several aromatic compounds are being examined with respect to the contributions made by high energy excited states. Molecular hydrogen production from the radiolysis of simple aromatic liquids with gamma rays is extremely low and these compounds are typically thought to be radiation inert. However, the yield of H2 can increase dramatically with increasing linear energy transfer, LET, of the incident radiation. This increase was observed to be almost an order of magnitude from gamma rays to 5 MeV alpha particles. Simple heterogeneous substitutions or the addition of side chains has little effect on H2 yields. Most important, the yield of H2 was found to be independent of the phase so the simple liquid aromatic compounds can be used to infer radiolytic effects of solid compounds, which are by nature more difficult to examine.
Radiolysis of Ices at Interfaces — Radiation chemistry studies of simple alcohol ices condensed on aluminum have been performed using a newly developed ice chamber based on material science techniques. Molecular hydrogen formation from frozen methanol, ethanol, and isopropanol is slightly lower at 77K than at room temperature presumably because of geminate recombination. Thin, nanometer, thick layers of alcohols were deposited and irradiated with electrons of 1 keV at 77K in the ice chamber. FTIR examination of these ices shows the conversion of the OH entity to an aldehyde in each of the ices. These studies are currently being extended to include condensed ices of simple amides.
Selected Publications | Top |
Roth, O., Dahlgren, B. and LaVerne, J. A.
Radiolysis of water on ZrO2 nanoparticles
J. Phys. Chem. C 2012 116, 17619-17624 link
LaVerne, J.A. and Baidak, A
Track effects in the radiolysis of aromatic liquids
Radiat. Phys. Chem. 2012 81, 1287-1290 link
Groenewold, G.S., Elias, G., Mincher, B.J., Mezyk, S.P. and LaVerne, J.A.
Characterization of CMPO and its radiolysis products by direct infusion ESI-MS
Talanta 2012 99, 909-917 link
El Omar, A.K., Schmidhammer, U., Rousseau, B, LaVerne, J.A., Mostafavi, M.
Competition reactions of H2O.+ radical in concentrated Cl- aqueous solutions: Picosecond pulse radiolysis study
J. Phys. Chem. A 2012 116, 11509-11518 link
Dhiman, S.and LaVerne, J.A.
Radiolysis of simple quaternary ammonium salt components of amberlite resin
J. Nucl. Mater. 2012 436, 8-13 link
Schmitt, C., LaVerne, J.A., Robertson, D., Bowers, M., Lu, W. and Collon, P.
Target dependence for low-Z ion charge state fractions
Nucl. Instrum. Methods Phys. Res. Sect. B 2011 269, 721-728 link