The photoelectric emission with low-energy ultraviolet radiation, whoes intensity is measured by using an atmospheric low-energy electron counter in the atmosphere, has been studied for Au surface and LB-films on Au. In order to investigate the energy distribution of electrons, spectro-scopic analysis is also made with a hemispherical spectrometer under vacuum. The observed spectra distribute with the kinetic energy of 0 eV∼(hv-φ) eV, where hy and φ indicate the incident energy and work function respectively, and shift according to the incident energy. The dependence of the photoelectron intensity on the incident energy in the atmosphere is almost the same as that of vacuum. However, the observed threshold energies for photoelectric emission in the atmosphere is slightly different from that in vacuum. The energy distribution of the cross section for the attachment of electron to oxygen molecule, which is supposed to be the carrier of low-energy electron in the atmosphere, might cause such a difference. Further, the mean free path of low energy electron is estimated for LB-film to be 15 Å in the atmosphere and 41 Å under vacuum. The difference between them can be partially accounted in terms of the difference of the threshold energies men tioned above.
View full abstract