Formation and Decay Processes of Superexcited Hydrocarbons in the Vacumm Ultraviolet Eange

摘要

Dynamics of superexcited molecules, which ahve internal energies higher than their ionization potentials, has been a subjects of current interest both in radiation research and in atomic collision research. Less is known, however, for polyatomic molecules in comparison with simple diatomic or triatomic molecules. To understand the neutraldissociation processes through molecular superexcited states, we have studied the subjects by two kinds of experiments at the Photon Factory in Tsukuba. One is the measurement of the fluorescence excitation spectra (FES) due to electronically excited fragments produced by neutral dissociation, and the other is the measurement of the absolute values of the photoabsorption (#sigma#_t), photoionization (#sigma#_i), and neural-dissociation (#sigma#_d) cross sections, and photoionization quantum yields (#eta# = #sigma#_i / #sigma#_t). the polyatomic molecules which we have studied so far are,