Professor of Chemistry and Physics, University of California, Berkeley; Director, Chemical Dynamics Beamline, Lawrence Berkeley National Laboratory
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Email:
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srl@berkeley.edu |
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Phone:
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(510) 643-5467 |
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Fax:
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(510) 643-1376 |
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Mail:
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209 Gilman Hall |
Professor Leone's research interests include ultrafast laser investigations of soft x-ray probing of valence and core levels, attosecond physics, state-resolved collision processes and kinetics investigations, nanoparticle chemistry, semiconductor epitaxy and nanodot formation, nanoscale probing with near field optical microscopy, CARS microscopy, and neutrals imaging.
Current projects are grouped along several main themes: Ultrafast laser molecular dynamics, including wave packets, x-ray probing, and attosecond pulse production and investigations; chemical dynamics of molecules, nanoparticles, and clusters; nanostructured materials investigations with scanned probe microscopies. Projects include: femtosecond laser molecular wave packet dynamics, ultrafast soft x-ray, time-resolved x-ray photoelectron dynamics, attosecond dynamics, surface/semiconductor growth and processing, near field and ultrafast optical microscopy of semiconductors and nanowires, infrared near field microscopy of polymers, epitaxial nanodot growth, vapor uptake and diffusion in polymers, photofragmentation and radical-radical reactions, aerosol chemistry, low temperature reactions for the chemistry of Saturn and Titan.
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Attosecond streaking of photoelectrons ejected from Ne atoms using isolated attosecond pulses to eject the electrons, overlapped with a few-cycle 800 nm streak field. |
Several examples are considered briefly. Ultrafast lasers are used to probe the dynamics of molecular motion on the time scales of vibrational, rotational, or electronic (Rydberg state) periods. The Leone group investigates coherent control properties by assembly of wave packets with varying amplitudes and phases of states. The study of molecular photodissociation by soft x-ray laser techniques has opened the way to analyze the simple breaking of a molecular bonds in greater detail. High order harmonics are produced by high fields in a rare gas and used to probe valence shell photoelectron spectra and core level spectroscopy of time-evolving systems, ranging from atoms to small molecules to metal clusters. Phase-shaping of the high order harmonics has been investigated. Transient x-ray absorption is used to probe alignment and molecular fragmentation pathways through core level spectroscopy. By using few cycle carrier-envelope phase-stabilized laser pulses, attosecond pulses are generated to study electronic timescales in molecules and clusters by ejecting inner shell electrons on attosecond timescales. An apparatus to probe photoelectron angular images with time-resolved high order harmonics is used to study outgoing electron waves and phases. Research also investigates the ultralow temperature gas phase kinetics for the atmospheres of Titan and Saturn, as well as to probe combustion dynamics through radical reactions. Heterogeneous chemistry is a significant new area of investigation, with applications to fuel droplet combustion and aerosol aging in the atmosphere.
Surface semiconductor processes, including epitaxial growth of materials, are another rich area of investigation. The formation of InGaN nanodots on novel substrates is investigated to achieve greater indium incorporation. New experiments are being explored in confocal microscopy, apertureless near field optical microscopy, and single pulse coherent anti-Stokes Raman microscopy with phase control, for example, to probe polymer films with chemical specificity, and to study ultrafast laser action in nanowire materials. Other new projects have been developed to study aerosol light scattering and spectroscopy, as well as surface probing of neutrals desorbed by scanning ion microprobes using the chemical dynamics beamline at the Advanced Light Source. Scanning transmission x-ray microscopy is used to probe polymer materials. Time-resolved x-ray microscopy using ultrafast soft x-rays is another novel direction for the future.
Dr. Leone received his B.A. in Chemistry at Northwestern University in 1970 and his Ph.D. in Chemistry at the University of California at Berkeley with Professor C. Bradley Moore in 1974. He was an assistant professor at the University of Southern California from 1974-76. He assumed a position with NIST and the University of Colorado in 1976 and became a full professor in 1982. Dr. Leone was a Fellow and staff member of the National Institute of Standards and Technology, a Fellow of JILA, as well as an Adjoint Professor of Chemistry and Biochemistry and a Lecturer of Physics at the University of Colorado. In 2002, he became Professor of Chemistry and Physics, University of California, Berkeley, and director of the chemical dynamics beamline at the Advanced Light Source, Lawrence Berkeley National Laboratory.
His numerous honors and awards include:
His research interests include laser-excited atomic and molecular dynamics, kinetic and spectroscopic investigations of excited states, energy transfer and dynamical processes of small gas phase molecules, alignment effects, ion-molecule reaction dynamics, semiconductor epitaxy and etching, nanostructures and nanoscale optical microscopies and dynamics, nanoparticle and aerosol chemistry, coherent processes and wave packets, femtosecond and attosecond dynamics.
The Leone Group expects to have a number of openings for postdoctoral associates and graduate students in 2007/2008 for projects on ultrafast molecular dynamics, especially using high harmonic generation, and new projects in chemical imaging and microscopy. Please contact Stephen R. Leone at SRL@berkeley.edu; phone (510)643-5467.
Postdoctoral candidates should arrange to have sent: curriculum vitae, 3 letters of reference, recent publications, and a summary of graduate grades.
Undergraduate students are encouraged to inquire about independent study research; please send resume and summary of grades.
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Email:
|
srl@berkeley.edu |
|
Phone:
|
(510) 643-5467 |
|
Fax:
|
(510) 643-1376 |
|
Mail:
|
209 Gilman Hall |