Speaker: Lars H. Andersen (IFA) Title: Electronic spectroscopy of large molecular ions performed by accelerator-based techniques Time: Today, 15.15 Place: Fysisk Auditorium Abstract: Molecular ions act as chromophores in a variety of proteins and they serve important purposes for example in energy harvesting and vision. Typically, protein interactions change the absorption wavelength (color tuning) as well as the speed and quantum yields of the molecular response of the chromophore. To have a reference for such interactions, we study the absorption properties as well as the molecular response times in vacuum, i.e. in an environment devoid of external perturbations (for example charges, dipoles and hydrogen bonding). In recent measurements with anionic chromophores we see signatures of electronically excited states, energetically far above the electron-detachment threshold. Perspectives for using UV radiation from ASTRID II together with a new electrostatic storage ring will be discussed. Peter Staanum and Nicolai Nygaard