Field enhanced photoemission: A new technique for the direct determination of the quasi-free electron energy in dense fluids

Previous experimental studies of the quasi-free electron energy V 0 ( ρ ) in dense fluids either directly measured V 0 ( ρ ) , using photoemission from an electrode immersed in the fluid, or extracted V 0 ( ρ ) from field ionization of a dopant dissolved in the fluid. In this letter, we present a new method to determine directly V 0 ( ρ ) , namely field enhanced photoemission. We show that this new method yields data comparable to those obtained from dopant field ionization, thereby making this method superior to direct photoemission studies. Moreover, unlike dopant field ionization, field enhanced photoemission is not limited by the solubility of a dopant in the fluid of interest.