Photoemission from Silver into AgCl, KBr, NaCl, and New Bands of Photosensitivity in AgCl

The work required to move an electron from a metal into an insulator has been investigated photoelectrically. The work function thus found was about 4.3 ev for Ag evaporated in vacuum on KBr (Fowler plot) as well as on NaCl (threshold wavelength). The photoelectrons become trapped in these crystals at vacant anion sites and may be released by $F$-band illumination. For Ag on AgCl a work function of 1.1 ev is measured at the low temperatures used to freeze out ionic conductivity.