The photoionization process of pyrene in non-polar solvent has been investigated using a
two-color two-photon ionization technique. The ionization spectrum near threshold of
pyrene in n-hexane was measured by a delayed
irradiation of a dye laser 20 ns after an N2
laser at total excitation energies of 5.9–6.22 eV. The two-photon ionization threshold of
pyrene was in the vicinity of 5.9 eV which is larger by 0.7 eV than that expected from the
onset of one-photon ionization. The ionization spectrum shows maxima at 5.92 and 5.99
eV which may be assigned to an autoionization process.
UV Resonant Two-Photon Ionization Spectrum of 1-Naphthol
