Many-Body Electronic Structure of Americium metal

TL;DR

This paper presents a novel spectral density functional method to simulate americium's electronic structure, revealing a pressure-induced valence change and providing insights into its unique properties and localization-delocalization transition.

Contribution

It introduces a new computational approach for many-body electronic structure and uncovers the pressure-driven valence transition in americium.

Findings

Americium exhibits a mixed valence regime with pressure-induced transition to 5f7 state.

The method explains americium's unique properties and localization-delocalization behavior.

The approach advances understanding of actinide electronic structures.

Abstract

We report computer based simulations of energetics, spectroscopy and electron-phonon interaction of americium using a novel spectral density functional method. This approach gives rise to a new concept of a many-body electronic structure and reveals the unexpected mixed valence regime of Am 5f6 electrons which under pressure acquire the 5f7 valence state. This explains unique properties of Am and addresses the fundamental issue of how the localization delocalization edge is approached from the localized side in a closed shell system.