  We present results of an ab-initio study of the electronic structure of 140
rare earth compounds. Specifically we predict an electronic phase diagram of
the entire range of rare earth monopnictides and monochalcogenides, composed of
metallic, semiconducting and heavy fermion-like regions, and exhibiting valency
transitions brought about by a complex interplay between ligand chemistry and
lanthanide contraction. The calculations exploit the combined effect of a
first-principles methodology, which can adequately describe the dual character
of electrons, itinerant vs. localized, and high throughput computing made
possible by the increasing available computational power. Our findings,
including the predicted "intermediate valent" compounds SmO and TmSe, are in
overall excellent agreement with the available experimental data. The accuracy
of the approach, proven e.g. through the lattice parameters calculated to
within 1.5% of the experimental values, and its ability to describe
localization phenomena in solids, makes it a competitive atomistic simulation
approach in the search for and design of new materials with specific physical
properties and possible technological applications.
