Invitation for Academia Copernicana PhD students to the lecture given by dr Maristella Alessio from the Department of Chemistry, University of Southern California.
Title of the lecture: Quantum Chemical Design of Molecular Magnets
Date: April 21st, 2022
Time: 6:00 p.m.
Platform: MS Teams
A reliable ab initio description of molecular magnets is key to developing novel moleculebased quantum devices, with the potential to be more efficient and easily tunable. However, quantum mechanical treatment of such systems is challenging due to their multiconfigurational wave functions, requiring a well balanced description of their constituent electronic configurations. Furthermore, theory to be useful necessitates efficient yet reliable approaches accounting for relativistic interactions and tools predicting the molecular magnetic behavior.
In this seminar, I will present a new computational protocol for computing magnetic properties of transition-metal complexes, which complements experimental investigations on the design of improved molecular magnets. Firstly, I will discuss the motivation and the theory behind such approach. The approach follows a state-interaction scheme in which spin-orbit coupling and the interaction with an applied magnetic field are treated as perturbations using equation-of-motion coupled-cluster (EOM-CC) wave functions. Temperature- and field-dependent magnetic properties (magnetization and susceptibility) are obtained by differentiation of the partition function computed using the energies of the perturbed EOM-CC eigenstates. The protocol is implemented within the ezMagnet software. Secondly, I will present the capabilities of the protocol by applications to a benchmarking set of mononuclear Fe(III), Fe(II), and Fe(I) molecular magnets, and show that the computed energy barriers for spin inversion, and magnetization and susceptibility data agree well with experiments. Finally, this study is complemented by the analysis of spinless transition density matrices and related transition natural orbitals, which explains the trends in magnetic anisotropy and barrier height of the Fe-based molecular magnets in terms of an easy orbital picture.