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.