We have a number of projects within the group that are suitable for all levels (Bachelor's, Master's, Ph.D.). The truly interdisciplinary nature of the field of molecular magnetism provides a great degree of flexibility and ensures that projects can be tailored to suit the individual student. Below are a number of possible projects. If you wish to discuss any of these further, or if you have a suggestion for a project not listed here, then please do not hesitate to get in touch with Jacob Overgaard (jacobo@chem.au.dk, building 1512-314).
Highly accurate diffraction data from either X-ray or polarised neutron diffraction can allow for an experimental determination of the density of the electrons/spins. This could then be used to explain the underlying properties that give rise to SMM behaviour in terms of orbital populations. We have many years of experience with these kinds of experiment, but they are only just starting to be applied to molecular magnets.
One of the most important properties of SMMs is their magnetic anisotropy, which is reason for the energy barrier towards relaxation of the magnetic moment. The magnitude of the anisotropy can be computed by quantum chemical means, but it is not always accurate. In our group, we develop new experimental methods to quantify the magnetic anisotropy, based on polarized neutron diffraction from both powders and single crystals. We are also exploring methods to achieve this using synchrotron radiation, for instance using resonant scattering.
We have built facilities to measure crystal structures under high pressure, using so-called "diamond anvil cells" or DAC. We use these to determine how molecular structures change when the crystals are compressed. In our research, we are particularly interested in how the magnetic properties change, and so far we have determined the crystal structure under pressure and then used computer calculations of the magnetic properties based on these compressed structures. We are currently working on developing pressure cells that can fit into the equipment we have for measuring magnetic properties, and this is research we would like help with.
The relationship between structural and magnetic parameters is a vital prerequisite for the rational design of improved magnetic compounds. Unfortunately, reliable correlations remain elusive for compounds containing highly anisotropic ions, particularly those that can predict the form of exchange interactions (ferro- or antiferromagnetic). Charge density methods could provide a wealth of valuable information for such studies.
Computational techniques are often used to aid in the rationalisation of magnetic behaviour, since the energy manifolds that dictate the magnetic properties are often very difficult to measure experimentally. Both DFT and ab initio methods (CASSCF) are used routinely to this end. Student projects could involve calculations on novel compounds being studied by charge density methods, and will be supported by experts working in theoretical chemistry here in Aarhus.
