An Iterative Second-Order Multi-Reference Linear-Response Method for Excitation Energies

• Applicant: Dr. Benjamin Helmich-Paris
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 467781355

From the current project we have learned that there is a strong coupling between singles and doubles configurations for some excited states. The newly developed MC-TDA(D) has limitations when this coupling is strong. With a second-order multi-configurational unitary coupled cluster (MC-UCC2) method, we would like to compute excitation energies with an improved accuracy for various types of electronic transitions. We are very interested in investigating the capabilities and the performance of both MC-TDA(D) and MC-UCC2 for excited states of transition-metal complexes and organic molecules with pi-systems. In case of transition-metal complexes, we are interested particularly in charge-transfer and ligand-to-ligand transitions for which established methods have significant limitations.

• DFG Programme: Research Grants