Energy absorption of free rare gas clusters irradiated by intense VUV pulses of a free electron laser

As one of the first experiments at the free electron laser of the TESLA Test Facility (TTF) the Coulomb explosion of Xenon clusters irradiated with high intensity pulses at a wavelength of 98 nm has been observed. Classical trajectory calculations have been performed in order to illuminate the energy absorption process. Comparison with typical parameters in the infrared regime shows that above barrier ionization is suppressed due to the fast oscillating field and thermionic ionization prevails. (C) 2003 Elsevier Science B.V. All rights reserved.