Pressure effect on electron localization in solid lithium

External pressure applied to a solid material causes modifications of the bonding which can provide a chemical explanations of phase transitions. The behaviour of the Electron Localization Function (ELF) has been examined for the body-centred cubic, face-centred cubic and (Ibar 43d-16) phase of lithium for a series of cell volumes accounting for external hydrostatic pressures in the 0-60 GPa range. It is shown that the ELF signatures of electron localization increase with the pressure. Moreover, the number of basins per atom is the high-pressure phases is less than in the low-pressure ones and therefore the basin population are larger in high pressure modifications. These results complement the study of Marques et al. Phys Rev Lett 106:095502 (2011) carried out on the C2c b ? 40 and C m c a ? 24 phases stable above 85 GPa.