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Dan Meisel
Hebrew University of Jerusalem, Israel:
B. Sc. (1967), M. Sc. (1969), and Ph. D. (1974)
Phone (574) 631-5457 Fax (574) 631-3646
e-mail: dani@nd.edu
Photochemically and radiolytically induced processes at the nanoscale |
Scientific Interests
Energy and Charge Transfer across Interfaces -Excitation and ionization in nanoparticles in suspension may lead to the transfer of charge carriers across the interface. We determine the distances and efficiency over which this transfer can occur before the competing annihilation and energy dissipation processes dominate. 
Metallic Nanoparticles under Irradiation – Metallic particles are efficient redox catalysts, transforming single-electron reducing radicals to multi-electron molecular products. Using microscopic spectroscopic techniques we study the interactions of the radicals with the metallic surface in an effort to understand the detailed mechanism for these reactions.
Solar Energy Conversion and Environmental Implications - The basic principles described above are of direct implications to power generation in nuclear plants, to the conversion of solar energy into chemicals, to environmental effects of energy generation & utilization, and to the use of ionizing radiation in radiotherapy. We incorporate the basic science conclusions obtained from fundamental studies of energy deposition and interfacial charge transfer directly into these technological issues.
Recent Accomplishments
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Radical-Particle Interactions in Metallic Nanoparticles – Reducing radicals react with metallic particles by electron-transfer, followed by proton-transfer reactions, ultimately leading to molecular hydrogen evolution. Using surface enhanced Raman spectroscopy we were able to estimate the overpotential under which the particles operate and to describe the changes that the particle undergoes during the catalytic hydrogen evolution from water.
Charge Separation Across the particle/Water
Interface – Suspensions of silica particles in water were exposed to ionizing radiation in an attempt to determine the escape probability of electrons from the solid particles into the water phase. It was discovered that all electrons that are initially generated in the silica appear as hydrated electrons even at the largest particles available. Their escape distance into the aqueous phase was estimated and it was concluded that none would escape from distance larger than 30 nm. Because of its relevance to radiotherapy, similar studies to determine the same parameters in metals are now underway.
Selected Publications | Top |
G. Merga, L.C. Cass, D.M. Chipman and D. Meisel
Probing silver nanoparticles during catalytic H2 formation
J. Am. Chem. Soc. 2008 130, 7067-76 link
G. Merga, R. Wilson, G. Lynn, B. H. Milosavljevic, and D. Meisel
Redox catalysis on “naked” silver nanoparticles
J. Phys. Chem. C 2007 111, 12220-6 link
T. Zidki, H. Cohen, D. Meyerstein and D. Meisel
Effect of silica-supported silver nanoparticles on dihydrogen yields from irradiated aqueous solutions
J. Phys. Chem. C 2007 111, 10461-6 link
G. Merga, B.H. Milosavljevic and D. Meisel
Radiolytic yields in aqueous suspensions of gold particles
J. Phys. Chem. B, 2006 110, 5403-8 link
D. Lahiri, B.A. Bunker, B. Mishra, Z. Zhang, D. Meisel, et al.
Bimetallic Pt-Ag and Pd-Ag nanoparticles
J. App. Phys. 2005 97, 094304 link
B.H. Milosavljevic, S.M. Pimblott and D. Meisel
Yields and migration distances of reducing equivalents in the radiolysis of silica nanoparticles
J. Phys. Chem. B 2004 108, 6996-7001 link
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