Alkali-metal structures above thes−dtransition

Abstract

Structural phase-stability calculations have been carried out by means of the linear-muffin-tin-orbitals method for Cs, Rb, and K, at pressures sufficiently high to have converted all valence electrons in these metals from $s$ to $d$ states. It is suggested that the stable phase of these new, experimentally accessible, $d$- band metals should at first be hexagonal-close-packed followed by higher-pressure transitions to Sm-type, double hexagonal-close-packed, and body-centered-cubic structures driven by the effects of hybridization. Core repulsion appears to play a key role in stabilizing these phases relative to more open structures.