Figure 2
From: Excitation spectra in fluids: How to analyze them properly
Dispersion relations in the 3D Lennard-Jones fluid at the temperature (a) 2.85 and (b) 6.03. Orange circles correspond to \({\omega }_{T}\) obtained with the two-oscillator model (5), black pentagons are maxima of the transverse part of current spectra in the two-oscillator model. Blue rhombs represent maxima of transverse current spectra \({C}_{T}(q,\omega )\) at different q values. The wavelength range highlighted by the gradient blue area corresponds to the transition from overdamped to non-overdamped excitations. The black solid and dashed lines are theoretical expansions Eq. (7) and its version with \({\beta }_{\ast }\equiv 0\), respectively, with the coefficients taken from the two-oscillator model.
