Multifrequency and Chemical Tuning Studies of V(IV) Quantum Spins

Complexes of the magnetic ion vanadium(IV) are at the frontier of molecular qubit research. Indeed, several recent investigations demonstrate that these ions are capable of spin relaxation times comparable to diamond’s nitrogen vacancy centers. In light of these exciting results, significant fundamental knowledge is still needed to further design these ions as qubits. For example, understanding the frequency dependence of V(IV) electron paramagnetic resonance properties underlies many applications, yet EPR studies are largely focused at only one frequency, X-band. Separately, understanding how ligand chemical composition affects spin relaxation times would enable the further improvement of relaxation times. Yet, the majority of research in this area is focused on vanadium ions surrounded by ligands that are composed entirely of carbon, oxygen, and sulfur. In this presentation, results from multi-frequency EPR analyses on families of vanadium(IV) complexes will be presented, with an eye toward the foregoing fundamental insight.