SYNCHROTRON-RADIATION-INDUCED PHOTOIONIZATION AND PHOTODISSOCIATION OF SMALL MOLECULES

Tunable synchrotron radiation makes possible detailed studies of molec ular photoionization and photodissociation. This is particular true if the induced reactions may be studied in various decay channels such a s formed ions and positive and negative fragments as well as fluoresce nce in different wavelength regions. We have performed studies of this kind in the low energy range (14 - 35 eV) using the Swedish synchrotr on facility MAX in Lund. A special detection channel has been construc ted for the purpose involving two sections, one low pressure chamber w ith a quadrupole mass spectrometer and one high pressure chamber for f luorescence detection using a variety of photomultipliers. The studies performed so far involve small fundamental molecules such as N-2[1,2] , O-2[3,4], CO[5] and NO[6] as well as CO2[7], methane[8] and neopenta ne[9]. While a great number of the observed lines are already known, s everal strong lines and series have been classified for the first time . The combination of information from the mass spectra and the fluores cence spectra contribute important information concerning autoionizati on and predissociation of the involved Rydberg states.