Index Introduction The Research at Rijnhuizen Results in 2008 Education, Training, Outreach and Public Information Output Appendix website Rijnhuizen Generation and Utilization of THz-Radiation Division FELIX The Generation and Utilization of THz-Radiation Division comprises groups that perform experiments in the terahertz spectral range. First of all, the division exploits the Free-Electron Laser for Infrared Experiments (FELIX). FELIX is operated as a user facility, providing continuously tunable radiation in the infrared spectral range of 4-250 µm, at peak powers ranging up to 100 MW in (sub)picosecond pulses. The radiation of FELIX is used by scientists from all over the world for research in (bio-) medicine, (bio-)chemistry and (bio-) physics. FELICE In 2003 the design and layout phase for a major extension of the FELIX facility with a project named FELICE was started; FELICE stands for Free Electron Laser for Intra-Cavity Experiments. This project involves the construction of a third beamline which can be operated interleaved with one of the two existing beamlines at a maximum repetition rate of 10 Hz for each line and is therefore in fact doubling the amount of beam time available to the users. The purpose of FELICE is to provide significantly higher infrared intensities for low-absorption, gas-phase experiments. In the summer of 2007, phase I of the FELICE beamline became operational and it is now open to in-house and external users.  Molecular Dynamics As an in-house user of FELIX, the Molecular dynamics group applies the FELIX radiation in various experiments in the field of gas-phase molecular spectroscopy and dynamics, mainly of “exotic” transient species. FELIX is ideally suited to perform such experiments, as it combines a wide wavelength tuning range, covering the infrared molecular fingerprint region, with high power and fluence. Systems studied include molecular ions, complexes, radicals, metal clusters (complexed with small organics), and biomolecules. Figure 2.13: View of the FELIX vault.