The Mechanism of the Transition of Solid Hydrogen to the Conducting State at High Pressures

Abstract

The change in the structure of solid hydrogen upon compression along the isotherm of 100 K near the transition to the conducting state has been investigated within the density-functional theory. The dependences of pressure and electrical conductivity on the hydrogen density have been calculated. The pressure range from 602 to 836 GPa has been found where the first peak of the pair correlation function arises at a distance of 0.92 Å, which corresponds to the interatomic distance in the molecular ${\text{H}}_{3}^{ + }$ ion. Notably, this distance does not change with an increase in density. A sharp increase in the electrical conductivity is also observed.