PHOTOIONIZATION QUANTUM YIELD FOR LIQUID SQUALANE AND SQUALENE ESTIMATED FROM PHOTOELECTRON EMISSION YIELD

An equation relating photoelectron emission yield to initial photoionization quantum yield in the condensed phase is derived. The equation is applied to the photoelectron emission yields from liquid squalane (C30H62, 2,6,10,15,19,23-hexamethyltetracosane) and squalene (C30H50, 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene) previously reported by the authors. On the assumption that the thermalization distance of photoelectrons is of a similar value to that of electrons produced with X-rays the photoionization quantum yields of these liquids in the energy region between 7 and 10.8 eV are estimated. The photoionization quantum yields are evidently less than unity and increase with increasing photon energy. The quantum yield for squalane increases monotonically whereas the one for squalene shows a change in its slope around the photoionization threshold of the sigma electrons.