THE ELECTRONIC-SPECTRUM OF WATER IN THE DISCRETE AND CONTINUUM REGIONS - ABSOLUTE OPTICAL OSCILLATOR-STRENGTHS FOR PHOTOABSORPTION (6-200 EV)

The electronic excitation spectrum and the associated absolute optical oscillator strengths for the photoabsorption of water have been determined in the energy region 6-200 eV using low resolution dipole (e, e) spectroscopy and TRK sum-rule normalization. In addition, detailed studies of the absolute photoabsorption oscillator strengths for the valence shell discrete electronic transitions of water have been made using high resolution dipole (e, e) spectroscopy (0.048 eV fwhm), from the first excitation threshold up to 30 eV. The present results are free of `'line saturation'' (i.e. bandwidth/linewidth interaction) effects which can lead to serious errors when absolute intensity measurements are made using conventional Beer-Lambert law photoabsorption methods.