Electron-optical studies of the photoelectric effect

[摘要] In this laboratory Carl F. J. Overhage, and elsewhere other experimenters, have found that the normal energy distribution of photoelectrons from sodium does not agree with the Fowler-DuBridge theory of surface photo-electric emission. A marked discrepancy occurs. It has been suggested that gas contaminations may produce a cathode barrier which varies in a complicated way over the surface, and that due to this, and different work functions of various crystal faces, cathode areas which are effective in producing emission vary with incident radiation energies. It has been also suggested that the normal energy distribution from a rough surface, i.e., surface elements inclined at angles to the field, may be different from that predicted by the Fowler-DuBridge theory.An electron-microscope has been constructed for observing the photoelectric emission from a sodium surface. Electron pictures of the emitting surface have been taken for a variety of incident light energies. At the magnification used (10 diameters) no significant difference was observed.The Fowler theory for emission at 0[degrees]K has been adapted to the case of a rough surface. This modified theory does not predict any altered shape of the normal energy distribution curves when the retarding fields are high although it does predict changes for low fields and for very rough surfaces.

[发布机构] University:California Institute of Technology;Department:Physics, Mathematics and Astronomy

[关键词] Physics