Energy of the quasi-free electron in dense neon

In this Letter, field ionization of O2 doped into Ne is used to extract the minimum energy V 0 of the conduction band in dense Ne, and a novel critical point effect is observed. These results represent the first complete view of V 0 from low density to the density of the triple point liquid for a repulsive fluid (i.e., a fluid with a positive zero-kinetic-energy electron scattering length). The recently developed local Wigner–Seitz model is shown to fit these data accurately both at noncritical temperatures and on an isotherm near the critical isotherm.