VUV LIGHT-INDUCED ELECTRON-EMISSION FROM ORGANIC LIQUIDS

Electron emission from low vapor pressure liquids induced by vacuum ul travoilet light was measured as a function of photon energy between 6 eV and 10.8 eV. Absolute quantum yields were determined for 17 organic compounds comprising hydrocarbons, phthalates, phosphates, dicarboxyl ic esters, amines and polysiloxane fluids. The quantum yields rise fro m 10(-6) to 10(-1) with increasing photon energy. Systematic changes o f the yields with the molecular structure of the liquids were observed . The photoemission threshold energies of 11 liquids have been determi ned in this work. The electron energy levels and the photoemission pro cess are discussed by taking into account the electronic properties of the isolated molecules, the influence of charge polarization, and the transport of hot electrons through the liquid/vapor interface.