The 4f shell of Yb can accomodate 13 or 14 electrons depending on a particular compound. This near degenracy of f¹³ and f¹⁴ valence states has deep consequences. Using LDA+DMFT we instigate continuous transition between the f¹³ and f¹⁴ valence states in elemental Yb induced by pressure and discuss it in terms of fluctuating and intermediate valence concepts.

Discovery of higher temperature superconductivity in MgB₂ brought about  a renewed interest in strongly coupled conventional superconductors.  Surprizingly  Li, one of the simplest possible  solids,  turns out to be  ~20 K superconductor when compressed.  We use  density functional electronic structure and linear response theory to investigate the origin of Li superconductivity and lattice dynamics and to link the effects to the Fermi surface topology.