Non-valence correlation-bound (NVCB) anions are molecular systems which bind an electron diffusely through electron correlation effects, which are not well understood. Many quantum mechanical methods fail to describe these systems due to an inability to describe the diffuse electron, resulting in a collapse of the singly occupied orbital onto the continuum. CIPSI is a selected configuration interaction (CI) approach that perturbatively selects determinants from the full CI space. We are interested in exploring if CIPSI is suitable for describing correlation effects necessary for the NVCB anion. A model NVCB anion system is (H2O)4-, which is a valuable due to the ability to tune the role that electron correlation plays in the electron binding energy. We present our findings for the ability of CIPSI to accurately describe the electron binding energy of (H2O)4-. We also explore the influence of the initial reference space on the electron binding energy. We highlight the need to describe the anion and the neutral wavefunction with comparable accuracy, which is not based simply on the number of determinants.

Selected configuration interaction description of (H2O)4-, a model non-valence correlation-bound anion system

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.