Accurate and interpretable representation of correlated electronic structure Tensor Product Selected CI.

The task of computing wavefunctions that are accurate, yet simple enough mathematical objects to use for reasoning, has long been a challenge in quantum chemistry. The difficulty in drawing physical conclusions from a wavefunction is often related to the generally large number of configurations with similar weights. In Tensor Product Selected Configuration Interaction (TPSCI), we use a locally correlated tensor product state basis, which has the effect of concentrating the weight of a state onto a smaller number of physically interpretable degrees of freedom.

Generalization of the Tensor Product Selected CI Method for Molecular Excited States.

In a recent paper [, 6098], we introduced a new approach for accurately approximating full CI ground states in large electronic active-spaces called Tensor Product Selected CI (TPSCI). In TPSCI, a large orbital active space is first partitioned into disjoint sets (clusters) for which the exact, local many-body eigenstates are obtained. Tensor products of these locally correlated many-body states are taken as the basis for the full, global Hilbert space.

Understanding the Nature of Weak Interactions between Functionalized Boranes and N/O, Promising Functional Groups for Gas Separations.

The separation of nitrogen and oxygen gases is considered as a very challenging process, since both O and N are nonpolar molecules with similar kinetic diameters. Electronic structure theory can provide a fundamental understanding of effects that can lead to selective binding of nitrogen or oxygen gas for the development of novel separation processes. Boranes can bind dinitrogen through a dative bond, where the boron acts as a σ acceptor and back-donates through π orbitals.