[en] Theoretical or Mathematical/ electrical conductivity ; Fermi level ; high-pressure effects ; interstitials ; liquid metals ; liquid-liquid transformations ; lithium ; localised states ; melting ; molecular dynamics method/ tetrahedral clustering ; molten lithium ; electronic transitions ; structural transitions ; electrical conductivity ; sp 3 bonded materials ; covalent bonding ; electron localization ; interstitial ; melting temperature ; low-symmetry crystalline phases ; Fermi level ; first principles molecular dynamics simulation ; Li/ A7125L Electronic structure of liquid metals and semiconductors and their alloys A7150 Localized single-particle electronic states A7115Q Molecular dynamics calculations and other numerical simulations (condensed matter electronic structure) A7215C Electrical and thermal conduction in amorphous and liquid metals and alloys A7130 Metal-insulator transitions and other electronic transitions A6250 High-pressure and shock-wave effects in solids and liquids A6470D Solid-liquid transitions A6470J Liquid-liquid transitions/ Li/el
[en] A series of electronic and structural transitions are predicted in molten lithium from first principles. A new phase with tetrahedral local order characteristic of sp 3 bonded materials and poor electrical conductivity is found at pressures above 150 GPa and temperatures as high as 1000 K. Despite the lack of covalent bonding, weakly bound tetrahedral clusters with finite lifetimes are predicted to exist. The stabilization of this phase in lithium involves a unique mechanism of strong electron localization in interstitial regions and interactions among core electrons. The calculations provide evidence for anomalous melting above 20 GPa, with a melting temperature decreasing below 300 K, and point towards the existence of novel low-symmetry crystalline phases.