PNNL

Abstract

Using X-­-ray Emission Spectroscopy (XES) and Absorption Spectroscopy (XAS), it has been possible to directly access the states in the unoccupied conduction bands that are involved with 5f and 6d covalency in oxidized Uranium. By varying the oxidizing agent, the degree of 5f covalency can be manipulated and monitored, for the first time clearly and irrevocably establishing the importance of 5f covalency in the electronic structure of the key nuclear fuel, uranium dioxide.