Next, we quantify the relationship between the energy of electrons and their momentum which is typically represented by the band structure of a material. However, in (disordered) liquid metals the first Brillouin zone cannot be rigorously defined, in contrast to periodic structures of crystalline solids. Nevertheless, a radial band structure has previously been measured, e.g., in a lead monolayer melted on a silicon surface. Analogously, we introduce here the concept of a radial band structure in 3D. Denoted here as a spherical band structure (SBS), it represents the energy-momentum relationship in a spherically symmetrical space, where the electron energy is plotted versus the magnitude of the wave vector k.