Bootstrap Embedding for Molecules in Extended Basis Sets

Quantum embedding methods are powerful tools to exploit the locality of electron correlation, but thus far many wave function-in-wave function methods have focused on small (e.g., minimal) basis sets. One major challenge for extended basis sets lies in defining consistent atom- or fragment-localized orbitals in spite of the larger spatial extent of the underlying atomic orbitals. In this work, we modify a particular form of quantum embedding, bootstrap embedding (BE), to the case of extended basis sets. We find that using intrinsic atomic orbital (IAO) localization schemes alongside BE converges to ∼99.7% of the CCSD correlation energy in 3-21G, 6-311G, and cc-pVDZ basis sets for reasonably sized fragments. These results mark an important first step in extending the success of embedding methods to properly studying dynamic correlation.