Photon-induced fluorescence spectroscopy (PIFS)

Photon-induced fluorescence spectroscopy (PIFS) using monochromatized synch rotron radiation for exciting the sample selectively and a fluorescence spe ctrometer with a position-sensitive photon detector for recording its fluor escence spectrum is a very powerful experimental technique especially for t he investigation of atomic and molecular photoionization and photodissociat ion. To reduce the contributions of higher harmonics of the undulator radia tion which are also transmitted through the primary monochromator a very co mpact He absorber was developed. With a He pressure of 30 mbar in the diffe rentially pumped gas cell of the absorber the fraction of the third harmoni c of the undulator transmitted through the monochromator was reduced by a f actor of 175 for an exciting-photon energy of the first order of 24.18 eV. (C) 2001 Elsevier Science B.V. All rights reserved.