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Research Group Opportunities Publications Links _____________    |
GRADUATE STUDENT NEEDED for Non-dipole inner-shell excitation spectroscopy of moleculesGOAL: To use a unique McMaster-built electron scattering spectrometer to study systematically quantitative cross-sections for non-dipole and dipole inner-shell excitation of molecules. This is a relatively unexplored area of molecular spectroscopy in which our group has particular expertise and instrumentation advantages. Spectroscopic surprises are found frequently - see Chem. Phys. Lett. 300 (1999) 676. Recent studies in Quasi-elastic electron scattering have shown surprising results which suggest our measurments may be a simple and direct probe of quantum entanglement. We are also comparing high-momentum trasfer valence electron energy loss spectra to corespondsing inelastc photon scattering and finding significant differences, which may suggest previous assumptions about inelastic electron scattering are invalid. NATURE of STUDIES: You will carry out systematic
studies of the inner-shell excitation spectra of a variety of small
molecules with variable scattering angles and impact energies. The overall
goal is to develop a sense of the chemical information contained in
this data through comparison of molecular series and comparison with
high level calculations. Extending quantum codes we currently use for
predicting dipole-regime spectra to the non-dipole transitions would
be an interesting and appropriate challenge for the right candidate.
You will also assist with the maintenance and further development of
this complex electron spectrometer. There would also be opportunities
to participate in synchrotron radiation experiments to complement the
electron scattering results.
SKILLS ACQUIRED: Knowledge of core excitation spectroscopy
(NEXAFS, ISEELS); knowledge of all aspects of instrumentation
(vacuum, mechanical, electronics, gas handling etc); programming
YOUR THESIS: would report your results, including
instrumentation improvements, and their analysis in collaboration with
theory. Target molecules are chosen to explore the relationship of inner-shell
cross-sections and the electronic and geometric structure. Themes of
current interest incude: range of validity of the first Born approxiamtion
(an assumtion about strength of interaction as a function of scattering
angle); and the relative importance of non-dipole and dipole transitions
of the type O 1ssu
to pu and
O 1ssg
to pu in CO2
and other molecules with symmetry-equivalent core excitation sites.
SPECIAL BENEFITS: This project best suits someone
with an interest in more fundamnetal aspects of science, or with a strong
interest in instrumentation. It would be an excellent preparation for
an academic career, as well as any position involving advanced instrumentation
and mathematical skills.
© 2010 A.P. Hitchcock / McMaster University.
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