"Exploration of Electronic Structure Theory in the Relativistic and Time-Dependent Frameworks"
Wednesday, Sep 11, 2024
Abstract:
In this presentation, I will discuss our recent works in the DePrince group in developing and applying relativistic and time-dependent (TD) electronic structure methods based on the coupled-cluster (CC) theory and its excited-state equation-of-motion (EOM) extension. I will summarize our recent adventures with TD-EOMCC, which is useful in investigating exci- tation phenomena relevant to molecular spectroscopy. In particular, we will look into funda- mental challenges inherent to CC/EOMCC theory, which arise due to the non-Hermitian na- ture of the theory and the projective equations employed in the CC/EOMCC computations.1 I will also describe some challenges associated with the so-called N-representability of the one-body reduced density matrix (1-RDM), which requires a quantum mechanical 1-RDM to be mappable onto a physical N-electron wave function, coming out of (TD-)EOMCC calculations.2 Last, but not least, I will discuss our ongoing works in implementing the relativistic flavors of high-level CC/EOMCC theories in a massively parallel quantum chem- istry software as well as highlighting potential challenges that one may face in relativistic calculations.3
REFERENCES
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1 S. H. Yuwono, B. C. Cooper, T. Zhang, X. Li, and A. E. DePrince III, J. Chem. Phys. 159, 044113 (2023).
2 S. H. Yuwono and A. E. DePrince III, J. Chem. Phys. 159, 054113 (2023).
3 S. H. Yuwono, R. R. Li, T. Zhang, K. A. Surjuse, E. F. Valeev, X. Li, and A. E. DePrince III,
J. Phys. Chem. A 128, 6521 (2024).
