| Dennison has designed, built and used a wide array of
electron scattering and spectroscopy techniques including Auger spectroscopy
(AES), scanning electron microscopy (SEM), secondary and backscattered
electron spectroscopy, low energy electron diffraction (LEED), high energy
electron diffraction (HEED), electron energy loss spectroscopy (EELS),
electron stimulated desorption (ESD) and adsorption (ESA), and (e,2e)
spectroscopy. Recent work with electron scattering has focused on the
electronic structure of carbon materials, particularly graphitic amorphous
carbon. Another active area of research is the measurements of energy-
and angular-resolved cross sections of secondary and backscattered electrons;
this has application to understanding the fundamental interactions of electrons
with matter, charging of spacecraft
in near-earth orbit, and scanning electron microscopy.
Dennison has investigated the structure and dynamics of amorphous solids, particularly amorphous carbon. His work has included theoretical modeling of the dynamics and measurements using infrared and Raman spectroscopy, electron energy loss spectroscopy, scanning tunneling microscopy and secondary and backscattered electron spectroscopy. Dennison has also studied the structure, dynamics, and
phases transitions of monolayer and multilayer films physisorbed on solids.
The work has focused on rare gases and non-symmetric molecules adsorbed
on magnesium oxide, graphite and amorphous carbon. X-ray, neutron and low-energy
electron diffraction structural probes, along with infrared spectroscopy,
inelastic neutron scattering and vapor pressure adsorption isotherm measurements,
have been used in this work. The studies have also included some computational
and theoretical modeling of adsorbate interactions in asymmetric and disordered
systems.
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