Abstract
The ionization energy of the polydiacetylene solid PTS has been measured by the Millikan–Pope–Arnold method (MPA). This energy is found to be 5.2±0.1 eV in contrast with ESCA results published previously (7±1 eV). The present results are consistent with recent a b i n i t i o calculations. The yield is found to go approximately as the maximum electron kinetic energy cubed.