Physical Society Colloquium
Interview for Faculty Position
The Magic of the In-Between:
Chemical Physics at the
Nanoscale
Oliver Monti
University of Colorado
An enormous body of scientific work exists to describe the nature of atoms
and molecules on the one hand and properties of bulk matter on the other
hand. Recent efforts have shown that there is a size regime - between
individual atoms and the essentially infinite physical structures associated
with the solid state - where entirely novel properties of matter emerge. This
talk is concerned with elucidating the unique physical and chemical
properties of single, confined structures on the nanometer length scale.
A major focus of this talk will be the multiphoton photogeneration of metal
nanoparticles in a diffraction-limited focal region. Simulations of the
absorption spectrum reveal a size distribution dominated by particles with
∼ 1 nm radii. Spectrally resolved laser excitation and emission studies
demonstrate that the likely luminescence source is surface-enhanced Raman
scattering, with spectral fluctuations occurring on a time scale comparable
to fluctuations in the total luminescence intensity. Such diffraction-limited
photoproduction methods for luminescent metal nanoparticles offer novel
routes toward optical data storage and nanometer scale molecular sensing.
Building on the tremendous power of photoelectron spectroscopy to elucidate
electronic structure of matter, I will discuss the design and implementation
of a spatially resolved photoionization microscope (SPIM). The chemical
selectivity and high spatial resolution make it possible to study
nanometer-sized non-fluorescent objects at the single-particle level. First
results on thin films and metal nanoparticles show the tremendous potential
of spatially resolved photoelectron spectroscopy.
Monday, February 16th 2004, 16:00
Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103)
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