Journal of Physical Chemistry, Vol.98, No.46, 11858-11862, 1994
The Photoionization Spectrum of Liquid Benzene
The photocurrent from neat liquid benzene has been studied for excitation energies from threshold to 10.3 eV and for externally applied electric fields from 1 to 50 kV/cm, Using a power law fit to the energy dependence of the threshold current, an onset of epsilon(t) = 7.65 +/- 0.1 eV has been obtained. The field dependence was fit to an exponential radial probability density for thermalized ion-pair separation distances with an average separation distance of (r) = 23 +/- 2 Angstrom at an excitation energy, epsilon, of 8.86 eV (1.2 eV above threshold). Photocurrent was too weak to establish a dependence of (r) on excitation energy. The quantum yield for photocurrent at 8.86 eV was determined by comparison with the photocurrent from TMPD in 2,2,4-trimethylpentane (isooctane) to be 6.5 x 10(-4) at zero field. From this, the intrinsic molecular ionization probability at epsilon = 8.86 eV was determined to be 0.6 +/- 0.3.
Keywords:PHOTO-IONIZATION;NONPOLAR LIQUIDS;FLUORESCENCE;PHOTOCONDUCTIVITY;RECOMBINATION;HYDROCARBONS;LIGHT;SOLVENTS;ENERGIES;TOLUENE