Photoconductivity and photoelectron emission of liquid squalane and squalene induced by vacuum-ultraviolet light

The photoconductivity of liquid squalane (2,6,10,15,19,23-hexamethyltetracosane, C30H62) and liquid squalene (2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, C30H50) was measured as a function of photon energy. The energy thresholds of photoconductivity and photoemission were determined. From the difference of these two values the energies of the electronic conduction levels V0(C30H60) = −0.15 eV and V0(C30H50) = −0.55 eV were estimated. Absolute quantum yields of free ions were measured at a field strength of 6.7 kV cm−1 in the photoconductivity experiment. The difference in yields of the photoconductivity and the photoelectron emission is discussed taking into account the escape probability from geminate recombination and the transport of photoelectrons in the liquid and through the liquid/vacuum interface.