Modern Optics and Spectroscopy Seminar
Molecular Spectroscopy and High Temperature
Plasmas:
Unlikely Bedfellows
Tom Gallagher
Department of Physics
University of Virginia
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Zero kinetic energy electron (ZEKE) spectroscopy of molecules
and dielectronic recombination of atomic ions and electrons
in high temperature plasmas do not sound as if they have much,
if anything, in common. However, in both cases the Rydberg states
converging to excited states of the ion play a crucial role,
and both processes are governed by similar physical processes.
Dielectronic recombination is the recombination of an ion and
an energetic electron through an intermediate autoionizing Rydberg
state converging to an electronically excited state of the ion.
In ZEKE spectroscopy it is the Rydberg states converging to
rovibrational states of the molecular ion which are important.
The essential similarities of the processes will be reviewed,
with emphasis on how the perturbing effects of, for example,
electric fields alter dielectronic recombination rates and lead
to observable ZEKE signals. Observations of the dielectronic
recombination of Ba ions from a continuum of finite bandwidth
will be described, as well as the extension of these ideas to
a new form of ZEKE spectroscopy in N0. |
Tuesday February 25, 12:00-1:00pm; Grier Room (34-401)
Refreshments served following the seminar
Sponsored by the George R. Harrison Spectroscopy
Laboratory and
the School of
Science, Massachusetts Institute
of Technology, and
the Rowland Institute
for Science.
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