Electron and phonon spectra dynamics and features of phase transitions in sodium at P=0-100 GPa

An electron and phonon spectra dynamics, features of structural phase transitions, and melting of sodium under the pressure ranging from 0 to 100 GPa are investigated. The electron and the phonon spectra of crystal sodium are calculated ab initio within the density functional theory by means of the software package LmtART-7 (see [1-3] and references herein), allowing the fully potential method of linear muffin-tin orbitals (FP-LMTO method). Earlier, this method was used in papers [4-6] for the calculation of a metals band structure within an atomic-spheres approximation (LMTO-ASA method). Using the Lindemann measure and the calculated phonon spectra, the theoretical values of melting points corresponding to the experimental data are obtained. Features of the electron and the phonon spectra dynamics in the melting curve maximum vicinity and within the structural transition range are discussed cI2 → cF4.