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Projects
Hydrogen storage
An effort to help understand
the fundamental interaction between hydrogen and nanomaterials
made of carbon, silicon, nickel, titanium and other metals. For this project our group utilizes
microscopy at UNLV and the Molecular Foundry at Lawrence Berkeley National
Laboratory, and various forms of spectroscopy at LBNL’s
Advanced Light source. The results may help to identify suitable material
candidates for hydrogen storage in a solid state matrix.
Polarized X-Ray-Emission Spectroscopy
Current experiments in
polarized x-ray-emission spectroscopy take place at the ALS’s
beamline 9.3.1 using our new x-ray emission endstation.
Initial
experiments have taken advantage of the atomic-site selectivity inherent to
core-level spectroscopy (i.e., core levels for different atoms are well
separated in energy), to study particular atomic sites in molecules. Over the
last few years we have revisited molecular systems similar to those
investigated in the pioneering studies, such as Cl-containing
methane-derivatives (CF3Cl, CF2Cl2,
etc.). We are now moving onto other
less-well-characterized molecules such as materials for hydrogen storage.
Resonant
Inelastic X-ray Scattering (RIXS): The
incident x-ray is sufficient to resonantly remove a core-level electron to a
higher unoccupied excited state.
Relaxation of this core-hole state is a two step process, an inner
shell electron filling the hole while simultaneously an x-ray photon is
emitted.
Non-Dipole: The dipole approximation refers to the
assumption that the expansion of exp(ik·r) for the interaction with the radiation field
can be set equal to unity if k·r is
small. Previous non-dipole
measurements at the ALS using electron time-of-flight techniques indicate
that the extent and significance of these effects is larger than might be expected.
For these experiments we must carefully study how the x-ray emission spectra
change depending upon the emission polarization angle relative to the
incoming photon beam axis.
Molecular Photoionization
and Photofragmentation Dynamics
Anion/Cation Spectroscopy:
Molecular Photofragmentation:
Atomic Photoionization:
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