On the Photoelectric Emission and Energy Structure of BaO

Spectral distributions of the photoelectric yield and energy distributions of the photoelectrons were obtained for BaO surfaces made in widely different ways. A small and variable yield for $h\nu <5\mathrm{}$ ev was attributed to unidentified imperfections. At the optical absorption edge, there was an effect much like the excitoninduced photoemission in alkali halides. At $h\nu \sim 5$ ev, an abrupt rise in the yield was ascribed to emission from an occupied band of electron states with an upper edge 5 ev below the vacuum level. Energy distributions were consistent with this interpretation.