Prediction of correlation energies using variational subspace valence bond
Abstract
In the variational subspace valence bond (VSVB) [G. D. Fletcher, J. Chem. Phys. 142, 134112 (2015)] method, the electronic orbitals comprising the wave function correspond to chemically meaningful objects, such as bonds, lone pairs, atomic cores, and so on. Selected regions of a molecule (for example, a single chemical bond, as opposed to all the bonds) can be modeled with different levels of basis set and possible methods for modeling correlation from the other regions. The interactions between the components of a molecule (say, a bond and a neighboring orbital) can then be studied in detail for their impact on a chemical phenomenon while avoiding the expense of necessarily applying the higher levels and methods to the entire molecule. This work presents the theoretical basis for modeling correlation effects between specific electron pairs by incorporating terms in the inter-electronic coordinates (“r12”) into VSVB. The approach is validated with calculations on small systems using single-reference wave functions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 23, 2022
- Source ID
- 10.1063/5.0098146
Entities
People
- Colleen Bertoni
- Graham D Fletcher
- Michael J. D’Mello
- Murat Keçeli
Organizations
- Argonne National Laboratory
- Intel Corporation