Increasing quantum yield of sodium salicylate above 80 eV photon energy: Implications for photoemission cross sections

The quantum yield of the visible scintillator sodium salicylate is found to increase in the incident photon-energy range 80–270 eV. Because of its use as a photon-flux monitor in recent gas-phase photoelectron spectroscopy measurements, previously reported partial cross sections for Hg (4f, 5p, and 5d subshells) and ${\mathrm{CH}}_3$I (I 4d subshell) in this energy range are corrected, and new values are reported. For Hg, the correction brings the experimental data into better overall agreement with theory. However, considerable uncertainty remains in the absolute scale derived from previous Hg photoabsorption measurements, and no single rescaling of the subshell cross sections could simultaneously bring all three into agreement with available theoretical calculations.