Evolution Of A Strongly Correlated Liquid With Electronic Density

Systems created by dissolving elemental metals in liquid ammonia are strongly correlated liquid metals where the electronic correlation strength can be easily changed by altering the electronic density. We study the plasmon in the lithium ammonia system as a function of electronic density using nonresonant inelastic x-ray scattering and use this to determine the long wavelength plasmon energy E(0) and the plasmon dispersion alpha as a function of electronic density. These parameters show the increasing influence of electronic correlations as we go to lower concentrations. The plasmon width is found to increase as we go to lower concentration. The implications of these results are discussed.