Abstract: The calculation of the ground-state electronic energy of a molecule is one of the primary tasks of quantum chemistry. In this talk, we survey recent progress for this task using benzene, the chromium dimer, and the FeMo cofactor as representative systems. We focus on computing the full configuration interaction (CI) energy, which for a given one-particle basis set is the exact non-relativistic electronic energy. Unfortunately, the computational expense of a full CI calculation scales exponentially with respect to system size, which prevents its use for almost all chemically relevant systems.

As an alternative, the last decade has seen the introduction of selected full CI methods that mitigate the exponential scaling of full CI by only including a subset of terms in the full CI wave function based on a selection criterion or rule. In this talk, we introduce selected CI and demonstrate how it has enabled computations of nearly exact electronic energies for larger chemical systems. We also compare it to other methods for approximating the full CI solution such as the density matrix renormalization group (DMRG).

Finally, we briefly discuss the application of quantum computing in quantum chemistry. Quantum chemistry is often referred to as a “killer app” for quantum computing in the mainstream media. We explore what the selected CI and DMRG methods reveal about the prospects of quantum computing in the field of quantum chemistry.

Bio: Kurt R. Brorsen has been an Assistant Professor in the Department of Chemistry at the University of Missouri since 2018. He was a postdoctoral researcher at the University of Illinois at Urbana-Champaign from 2014-2018 and received his Ph.D. in Physical Chemistry from Iowa State University in 2014. His research focuses on the development of new ab initio quantum chemistry methods to include nuclear quantum effects in computational chemistry calculations.