Optical and magnetic properties of organoactinide complexes an application of relativistic density functional theory

Abstract

The discovery of slow magnetic relaxation in certain transition metal-oxo clusters revealed a new family of magnetic materia Is known as single-molecule magnets. Such molecules possess a high-spin ground state (with total spin S) for which spin-orbit coupling results in a zero-field splitting of the (2S + 1 )-fold degeneracy in a manner that creates a thermal relaxation barrier and gives rise to magnetic bistability at low temperature. Two major goals of research in this area are generating new molecules with larger relaxation barriers and understanding the quantum tunneling processes that can sho1tcut the ban-ier. The greater radial extension of the 5/ valence orbitals of actinides can potentially provide increased overlap with bridging ligand orbitals, thereby enhancing the concerted magnetic behavior between bridged metal centers within a single cluster unit. Researchers have confronted the intricacies of the magnetic exchange in a number of interesting ways, often with the goal of identifying and, to the extent possible, quantifying ferro- or antife1TOmagnetic exchange coupling. Understanding these exchange interactions not only is essential to the development of models for the basic electronic stmcture of the Velements but also may represent the key to producing the first actinide-based SMMs. In this work we present the theoretical investigation about the magnetic and optical properties for a group of organoactinide complexes. Our calculations reveal that the electron mobility (delocalization) and relativistic effect pa1ticularly spin-orbit coupling have a principal role for a good description of these properties in this kind of molecule. Also we propose sorne molecular models with desirable structural parameters when the optical and magnetic properties detennined should open the door to the design of new materials with potential technological applications.