Solid State Ionization Potentials of Some Aromatic Organic Compounds

The ionization potentials of a number of solid aromatic organic compounds have been determined by photoelectric threshold measurements. These are compared with literature values of the gaseous ionization potentials and the solid-state surface values seem to be approximately 1¼ v smaller. The relation between the ionization potential of a molecule within a crystalline lattice and that in the surface of the lattice is described, and the significance of the bulk ionization for conductivity of organic molecular lattices is discussed.