Systematic laser-driven control of
photochemistry
Vacancies exist for a 3 year postdoc position and
PhD student in the Department of Chemistry at University College London. These
posts are part of a grant funded by the EPSRC (UK Engineering and Physics
Sciences Research Council). PhD candidates must be nationals of an EU country
and have a good degree in Chemistry, Physics or related discipline. Postdoc
candidates may be of any nationality and have a good experimental background in
some or all of, ultrafast lasers, photoelectron imaging, coherent control.
Prospective applicants should make informal contact
by email or telephone:
Professor Helen Fielding
Department of
Chemistry
University College London
20 Gordon Street
London WC1H
0AJ
UK
Project description
During the last few years it has become possible to use femtosecond lasers
to control photochemical reactions. The most successful approach has been to
shape the femtosecond laser pulse by changing the relative phases between the
various wavelengths supported within its broad bandwidth. This has the effect of
changing the quantum interferences between the various components of the
molecular wave packet launched onto an electronically excited potential energy
surface. By combining this phase-control with a learning algorithm that receives
feedback from the experiment, it is possible to optimise the phases of the laser
field to steer the photochemical reaction along a specific pathway. Shaped
optical waveforms can be thought of as a new class of chemical reagent that has
the capability of changing the output of a photochemical reaction by making and
breaking bonds at will. The technological achievements currently surpass the
development of our understanding of the mechanisms of optical control. Thus,
despite some truly impressive demonstrations of optical control in organic,
organometallic and biological photochemistry, we are still a long way away from
possessing the necessary expertise to systematically drive photochemical
reactions. This proposal aims to develop this capability. It brings together two
well-established groups with expertise in the experimental applications of
ultrafast lasers to coherent control (Fielding, University College London) and
quantum chemistry calculations of photochemical reactions (Robb, Imperial
College London). This unique team with its combined strengths in experiment and
theory is ideally placed to develop the proposed state-of-the-art machinery to
investigate the links between optical phase and the shape of a molecular
potential energy surface, and hence to achieve the ultimate goal of being able
to drive photochemical reactions intuitively. Ultimately we aim to be able to
design the pulse shapes intuitively.