Structural change of compressed Xe as a phase transition preceding metallization

A structural transition from f.c.c. to b.c.c. is suggested to occur for solid Xe at high pressure. This phase transition is shown to precede the metallization, and accordingly brings about a metallization pressure 0.82 Mbar which is closer to the experimental value 0.33 Mbar than the previous estimate 1.30 Mbar with f.c.c. as the assumed structure. The first-order effect of the spin-orbit coupling is also studied with an improved transition pressure 0.66 Mbar. These studies have been done consistently by means of the APW method combined with the local-density scheme.