|Dato||tor 11 apr|
|Tid||15:15 — 16:00|
Matrix spectroscopy has the advantage that the atoms or molecules being probed can be isolated and cooled, but the matrix holding the "sample"
usually has a significant effect on the spectra. These effects can be minimized by using superfluid helium-4 as matrix. Therefore, spectroscopy of helium-4 nanodroplets doped with single atoms or molecules or clusters of them has become a versatile experimental tool.
Interpretation of spectra obtained in this quantum matrix require knowledge about the influence of helium on the dynamics of the probed atom or molecule. In my presentation, I will give an overview of calculation methods for this non-trivial quantum many-body system, based on Monte Carlo simulations, but also on traditional many-body techniques. I present some results on rotational spectra of neutral and ionic molecules inside and on the surface of helium clusters, and on the formation of alkali-helium exciplexes, and discuss the influence of superfluidity of helium on molecule rotation spectra. Experiments of large organic molecules and of metal clusters in helium-4 have gotten much less attention from the theoretical physics and chemistry community since accurate interactions potential are not known in this case. We are tackling this problem with a phenomenological approach to obtain the all-important interactions between the dopant and the He atoms.
Coffee/tea and cake will be served from 15:05