Equation of state and electron localisation in fcc lithium

We present an improved equation of state for the high-pressure fcc phase of lithium with ambient temperature experimental data, extending the pressure range of previous studies to 36 GPa. The accompanying density functional theory calculations, which reproduce the experimental equation of state, show that with increasing density, the phase diverges from a nearly free electron metal. At the high pressure limit of its stability, fcc lithium exhibits enhanced electron density at the octahedral interstices with a high degree of localisation.