Selected Configuration Interaction in a Basis of Cluster State Tensor Products
The paper presents tensor product selected configuration interaction (TPSCI), a novel method that enhances selected configuration interaction (SCI) by utilizing local molecular structures to reduce the number of SCI variables. By grouping orbitals into clusters and employing many-particle cluster states instead of Slater determinants, TPSCI achieves significant computational efficiency and accuracy. The method is particularly effective when cluster states are defined using Tucker decomposition of the SCI vector.