The Angular Distribution of Photoelectrons Ejected by Polarized Ultraviolet Light in Potassium Vapor

Light of wave-lengths in the region of 2400A selected by a monochromator and polarized by a pile of quartz plates illuminated a jet of potassium vapor. The lateral directions of emission of the photoelectrons relative to the electric vector were studied. Though the electrons were ejected with energies less than one equivalent volt, the experiments were definite in establishing that the most probable direction of ejection is that of the electric vector and that the angular distribution varies as the square of the cosine of the angle between the electric vector and the direction in question. This result is in accord with predictions of the wave mechanics for a spherically symmetrical atom and incidentally therefore constitutes additional evidence that molecules do not play an appreciable part in the observed photo-ionization of potassium vapor.