Abstract

Leveraged by the technological progress of high-performance scientific computing over the past half-century, the field of quantum chemistry has flourished notably. As a result, molecular properties of small- to modest-sized species may nowadays be computationally predicted to within unparalleled accuracy. This is particularly true in the wake of the recent renaissance of full configuration interaction (FCI)-level methodologies, albeit only if these can prove themselves sufficiently robust and versatile to be routinely applied to a variety of chemical problems of interest. In this talk, one such avenue towards FCI -level results in medium to large one-electron basis sets, the recently introduced many-body expanded full configuration interaction (MBE-FCI) method [1-4], will be discussed. Specifically, I will review the fundamentals of MBE -FCI theory for states of any spin multiplicity – be they dominated by weak or strong electron correlation – in addition to recent capability enhancements.

Eriksen, J. J., Lipparini, F.; Gauss, J.: Virtual Orbital Many-Body Expansions: A Possible Route Towards the Full Configuration Interaction Limit. J. Phys. Chem. Lett., 8, 4633 (2017) [2]: Eriksen, J. J., Gauss, J.: Many-Body Expanded Full Configuration Interaction. I. Weakly Correlated Regime. J. Chem. Theory Comput., 14, 5180 (2018)
Eriksen, J. J., Gauss, J.: Many-Body Expanded Full Configuration Interaction. II. Strongly Correlated Regime. J. Chem. Theory Comput., 15, 4873 (2019)
Eriksen, J. J., Gauss, J.: Generalized Many-Body Expanded Full Configuration Interaction Theory. J. Phys. Chem. Lett., 10, 7910 (2019)