CAREER: Theories for Magnetic Properties of Lanthanide and Actinide Complexes

  • Shiozaki, Toru (PD/PI)

Project: Research project

Project Details

Description

Overview: The research objective of the program proposed herein is to understand and predict magnetic properties of lanthanide and actinide complexes by developing fully relativistic electronic structure theories for sizable (100–150 atomic systems and a few heavy atoms), open-shell molecules of quasi-degenerate character. Our proposed research aims to realize rational design of single molecule magnets and magnetic materials. It is proposed to develop electronic structure theories for such systems on the basis of the fully relativistic four-component Dirac equation because the spin–orbit and spin–spin couplings in lanthanide and actinide complexes are beyond the perturbation regime. Intellectual Merit: The breakthrough that our research promises is to realize predictive electronicstructure theories for lanthanide and actinide complexes that are applicable to real systems of chemical interest, enabling us to compare directly with experimental studies. The research projects have four components: (1) Scalable relativistic multi-configuration theories will be developed to determine zero-field splitting of f-element complexes. The density-fitted Dirac–Fock algorithm, which was applied to systems with 100 atoms and a few heavy elements in our prior studies, will be extended to open-shell theories. (2) An active-space decomposition strategy, recently developed by us in the non-relativistic framework, will be extended to model the direct exchange and superexchange interactions between spins on metal centers and bridges. The tensor decomposition of a coefficient matrix is proposed, with which the theory can be seen as a low-entanglement wave function ansatz using a fragment active space as a “site.” (3) Theories for f-element complexes interacting with a magnetic field will be developed to simulate electron paramagnetic resonance (EPR) spectra and field-induced single molecule magnets. The so-called London orbitals, which circumvent the gauge-origin problem, will be employed in the fully relativistic framework. (4) Relativistic multireference electron correlation methods will be implemented into parallel computer programs with the aid of an automated code generation approach. The focus will be on the development of electron correlation theories that can treat multiple states with an equal footing. Broader Impacts: The proposed research will open up a new field in computational research by enabling simulations of magnetic properties of large heavy-element complexes with fully relativistic electronic structure theories. The computer programs that implement the proposed theories and algorithms will be made freely available to the broad community (from theory and algorithm developers to computational chemists working on applications, and to the public) under the GNU Public License. In concert with the program development in the proposed research, the educational component of this proposal seeks to develop web-based learning modules for computational aspects of physical chemistry. Provided that the computer resources available to us continue to grow exponentially, and that computation-aided chemistry research is rapidly expanding, it is of vital importance to prepare undergraduate chemistry students for computational approaches, not as an optional subject, but as a part of the core physical chemistry program. The modules will take advantage of the modern object-oriented design to minimize unnecessary learning overhead. They will be disseminated on the portal website of NSF-supported “nanoHUB.org,” whose infrastr
StatusFinished
Effective start/end date3/1/142/29/20

Funding

  • National Science Foundation (CHE-1351598)

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