# f-electrons in chemistry of heavy transition metals

In one lecture on recent MCR-X conference I was puzzled by a side-note "f-hole is critical to describe DoS of $\ce{IrO2}$ correctly." The context was DFT periodic plane-wave calculations with pseudization for core electrons.

This implies, that f-electrons are somewhat involved into chemistry of Ir. More precisely, it seems that polarizability of f-shell affects subsequent d-shell in somewhat dramatic way.

Could someone point at relevant articles, preferably discussing the matter from both ab-initio and experimental perspective? Bonus points for generalization of the matter: d-electrons affect chemistry of heavy p-elements in no less way.