SEMINAR      Thursday 3rd November 2005 - h. 15:00  Auditorium B. Touschek     C. Pellegrini (UCLA) The development of X-ray free-electron lasers and ultrafast science at atomic and molecular scale Abstract <>     After many years of research and development an X-ray free-electron laser (X-FEL) operating in the 0.1 nm spectral region, the LCLS, first proposed by C. Pellegrini in 1992, is now being built and is expected to be completed in 2008.    Another X-FEL operating at the same wavelength is being proposed at DESY as an European project. Other similar projects are being developed in Japan, China and Korea.    The X-FEL will produce coherent photons at about 10 keV, with high intensity and femtosecond pulse duration. Using these  properties it will be possible for the first time to explore matter at the scale of length and time characteristics of atomic and molecular systems, thus opening a new field of science.