Fully funded PhD studentship
Femtosecond Photoelectron Spectroscopy of Fullerenes
Eligibility: UK and other EU nationals only.
Supervisor: Prof. Eleanor Campbell, School of Chemistry, University of Edinburgh
To start as soon as possible
Fullerenes are nanomaterials that have properties intermediate between those of large
molecules and those of bulk materials. They are becoming increasingly important as
electron-acceptor constituents of organic solar cells and doped fullerene crystals show the
highest critical temperatures of any “organic” superconductors. In spite of their
considerable interest as new organic electronic materials, surprisingly little is known
about the fundamental properties of the excited electronic states of the molecules and
how these develop into band structure as aggregates or crystals are formed. Evidence has
recently been found, using scanning tunnel microscopy, for the presence of diffuse
hydrogenic orbitals associated with fullerenes deposited on a metal substrate. These so-
called “superatom” states (SAMO) are distinct from the molecular s-and p-orbitals that
form through hybridization of the s and p orbitals on the carbon atoms. Instead of being
bound to individual carbon atoms the SAMOs assume the radial and angular distributions
of spherical harmonic functions that are defined by the central potential of the hollow C60
core and thus look like large, relatively simple atomic orbitals. When the fullerene
molecules self-assemble into chains, the diffuse orbitals are seen to readily combine into
delocalized bands and are predicted to play an important role in defining the electronic
properties of fullerene-based materials. We have recently found evidence for the presence
of these SAMOs in gas phase photoelectron spectroscopy of fullerenes with fs laser
pulses. Gas phase studies have the potential to provide more detailed information about
these unusual molecular states and will provide a stringent test of theoretical predictions.
This project, funded by the Leverhulme Trust, will expand on the initial investigations to
study the properties of SAMOs for a range of hollow fullerene-based molecular systems
(functionalized fullerenes, endohedral fullerenes, small carbon nanotubes). The aim will
be to understand how the properties of the orbitals can be tuned by modifying the
fullerene cage, ultimately leading to the development of materials with specific electronic
properties. The project will combine experiment and theory. Advanced experimental
techniques such as velocity map imaging photoelectron spectroscopy using amplified,
wavelength-tunable fs laser pulses will be used to probe the properties of the SAMO
excited states. The experimental work will be complemented by theoretical calculations
of photoelectron angular distributions using time-dependent density functional theory.
You should have, or be expecting to achieve, a first or upper second class Honours
degree, or equivalent, in chemistry, physics or chemical physics.
Please address informal enquiries to Prof. Campbell. For the formal application
procedure see: www.chem.ed.ac.uk/studying/postgraduate_research/apply.html.
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