Hannover 2003 – wissenschaftliches Programm
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A: Atomphysik
A 13: Cluster und Potentialstreuung
A 13.6: Vortrag
Donnerstag, 27. März 2003, 12:15–12:30, F128
Multiphoton absorption of rare gas atoms and clusters induced by excitation with intense VUV photons from a FEL — •Tim Laarmann1, Hubertus Wabnitz1, Joachim Schulz1, Peter Gürtler1, Wiebke Laasch1, A. Rubens C. de Castro2, Anja Swiderski1, and Thomas Möller1 — 1Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22603 Hamburg, Germany — 2LNLS 13084-971 Campinas SP Brazil and IFGW-UNICAMP 13083-970 Campinas SP, Brazil
This contribution reports on results of the interaction of intense VUV pulses with rare gas atoms and clusters. In recent years much effort has gone into the understanding of the interaction of intense visible and infrared femtosecond laser pulses with matter, especially with clusters. Very recently the free electron laser (FEL) at DESY has reached a gain of 106 and provides gigawatt pulses of 100 fs length and of tunable wavelength below 100 nm [1]. The tunability is particularly interesting because the wavelength regime covers the ionisation energy of Xe clusters [2], as well as the excitonic bulk and surface absorption bands of Ar clusters. On the other hand, it is not possible to populate electronically excited states in He atoms by the absorption of one FEL photon. By varying the photon energy, resonant and non-resonant multiphoton ionization can be induced. In this contribution we present time-of-flight mass spectra and photoemission spectra in order to discuss the influence of excitation energy and power density on the energy absorption of rare gas atoms and clusters. [1] V. Ayvazyan et al., Phys. Rev. Lett. 88, 104802 (2002) [2] H. Wabnitz et al., Nature 420, 482 (2002)