SCIENCE AT THE EDGE SEMINAR SERIES

Interdisciplinary Physics Seminar

Friday, 14 September 2012 at 11:30am

Room 1400 Biomedical and Physical Sciences Bldg.

Refreshments at 11:15

Speaker: Paul Corkum
         JASLAB, University of Ottawa and National Research Council of Canada

Title:   Catching Electrons with Light

Abstract:

Many scientists would say that it is intrinsically impossible to image a
molecular orbital.  A typical comment might be "Orbitals are but a mathematical
construct -- a convenience for designing chemical reactions."  This lecture will
show that orbitals (specifically Dyson orbitals) are measurable.

We exploit an intense light pulse for this purpose.  In intense infrared light,
an electron tunnels from a molecule.  After tunneling, the electron wave packet
moves under the force of the light's electric field.  The electron is first
carried away from the molecule by the light wave and then driven back to it,
where it interferes with the unionized portion of the orbital from which it just
separated.  This electron interference creates attosecond XUV pulses -
the shortest pulses ever generated.  The generated XUV radiation also contains
all the information needed to determine the amplitude and relative phase of the
orbital.

The lecture will conclude by describing how we might "film" orbital changes
during a photochemical reaction - an upcoming molecular movie.