  Pressure induced interaction between core electrons, the core level crossing
(CLC) transition has been observed in hcp Os at P~400 GPa [L. Dubrovinksy, et
al., Nature 525, 226-229 (2015)]. In this work, we carry out a systematic study
of the influence of pressure on the electronic structure in all metals of the
5d series (Hf,Ta,W,Re,Os,Ir,Pt,Au) using first-principles electronic structure
calculations. We have found that CLC is a general effect for this series of
metals. While in Pt it occurs at ~1500 GPa, at a pressure substantially higher
than in Os, in Ir it occurs already at 80 GPa. Moreover, we predict that in Re
the CLC transition may appear at ambient pressure. We analyze the shifts of the
CLC transition pressure across the series within the Thomas-Fermi model, and
show that the effect has many common features to the atomic collapse in the
rare-earth elements.
