Inelastic X-ray Scattering Studies of a Highly Correlated Liquid Metal

"We have used inelastic x-ray scattering to study the plasmon as a function
of electronic density in the highly correlated liquid metal created by
dissolving lithium in liquid ammonia. Measurements with a resolution of 100
meV were taken on the medium resolution spectrometer (MERIX) on the new
inelastic x-ray scattering beamline at Sector 30 of the APS. The plasmon
energy as a function of momentum gives information about the
electron-electron interactions. Plasmon linewidths contain information about
the coupling of the plasmon to other excitations. As the electronic density
is lowered we find an increasing deviation of the electronic properties from
the Random Phase Approximation. In addition, we find a surprisingly large
increase in the plasmon linewidth, indicating that new decay channels have
opened up in the system"