Fig. 1. Electron localization function (ELF) of (a) fcc-Li at 40 GPa and (b) hP4-Na at 300 GPa (isosurface = 0.75). The charge states of atoms and interstitial quasi-atoms (ISQs) are indicated. Note the prominent charge transfer and polarization. (c) and (d) show the ELF in the (1 1 0) plane of (a) and (b), respectively.

Fig. 2. Phonon dispersions of isotropic fcc-Li at 40 GPa [(a) and (b)] and anisotropic hP4-Na at 300 GPa [(c) and (d)] calculated using Bader charge [(a) and (c)] and Born effective charge [(b) and (d)] (dot-dash lines), which are compared with the bare results obtained without accounting for the LRCI contribution (dotted lines).

Fig. 3. (a) Phonon dispersion of hP4-Na at 300 GPa calculated with artificially varied ε^∞. (b) Variations of Δω = ω_LA − ω_TA with ε^∞ in fcc-Li at 40 GPa and hP4-Na at 300 GPa.

Fig. 4. Phonon dispersions of (a) fcc-Li at 40 GPa and (b) hP4-Na at 300 GPa calculated with different values of effective mass M_ISQ.