PHOTOELECTRON EMISSION BY SOLUTIONS

A detailed experimental study is reported of electron photoemission at a solution-nitrogen interface by aqueous solutions of potassium or sodium ferrocyanide. Old work on this problem is briefly reviewed as well as similar studies with organic systems and alkali metals in liquid ammonia. The following topics are covered: outline of experimental methods; variations of collected current with field strength and gas pressure; dependence of electron drift velocity in gases on field strength and pressure; plot of the reciprocal of current against the reciprocal of electron drift velocity; application of this plot to the determination of the emitted current and the average velocity and energy of electrons at emission; dependence of emitted current on field strength and possible explanations based on the photoelectric Schottky effect and/or field penetration in solution; correlation with double layer structure; spectral response for the collected current and determination of the threshold at 236 mμ for 0.1M K4Fe(CN)6; correlation with absorption band for charge transfer to solvent; influence of ionic valence and spectra] shift.