Supported by:
Participating institutions:
The Aarhus group performs research on a multitude of molecular physics
topics related to astrobiology:
Experiments on damage to isolated biomolecular (DNA and RNA nucleotides
and peptides) systems on the ELISA electrostatic storage ring at Aarhus
by low energy electrons and UV light in order to elucidate radiation
damage in a harsh environment relevant to the early Earth.
Solution-phase experiments on DNA segments using the ASTRID synchrotron
radiation facility at Aarhus (ISA) to obtain circular dichroism spectra
extending into the VUV. Such experiments shed light on the electronic
coupling between nucleobases and are relevant to the survival of DNA
strands under the VUV stress associated with the Earth before the
formation of an ozone layer.
Studies of the electronic structure of macromolecular ions, in
particular biochromophores, energy conversion and flow processes after
photoexcitation. Experiments are carried out with state-of-the-art
equipment at the University of Aarhus, for example fs-lasers and again
the storage ring ELISA.
Molecular astrophysics on surfaces. Detailed surface science experiments
are performed aimed at uncovering the physical mechanisms controlling
interstellar surface chemistry. The experiments involve the formation of
simple molecules, such as molecular hydrogen and water, as well as other
larger, astrobiologically relevant, molecules, under interstellar
conditions. We use a wide range of surface science techniques including
scanning tunneling microscopy, thermal desorption spectroscopy, laser
desorption and time-of-flight techniques as well as resonance enhanced
multi-photon ionisation. The combination of these techniques makes it
possible to obtain atomic scale information on surface reactions and
surface structures under conditions of interstellar relevance. Future
experiments within the area of astrobiology include investigation of
possible dust grain surface formation routes for prebiotic molecules,
self assembly of biologically relevant molecules and the interaction of
UV-light and surface adsorbates under conditions mimicking
interstellar and star forming regions.
Investigations into the interactions of very low energy cold electrons
with solid material. Using the ASTRID synchrotron at Aarhus (ISA) we
create very high resolution electron beams with an energy spread of
1-2 meV. Cold electron beams are guided onto solid material and their
interaction with these solids is studied. This is a completely new topic
for the very low energies of a few hundred K and below investigated here.
The processes which we study are directly relevant to the fate of ices
in the interstellar medium and may be a key to understanding the
formation of prebiotic molecules in space, such as the 70-80 amino
acids found in the Murchison meteorite.
