Generalization of Block-Localized Wave Function for Constrained Optimization of Excited Determinants

Adam Grofe, Ruoqi Zhao, Andrew Wildman, Torin F. Stetina, Xiaosong Li, Peng Bao, Jiali Gao

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The block-localized wave function method is useful to provide insights on chemical bonding and intermolecular interactions through energy decomposition analysis. The method relies on block localization of molecular orbitals (MOs) by constraining the orbitals to basis functions within given blocks. Here, a generalized block-localized orbital (GBLO) method is described to allow both physically localized and delocalized MOs to be constrained in orbital-block definitions. Consequently, GBLO optimization can be conveniently tailored by imposing specific constraints. The GBLO method is illustrated by three examples: (1) constrained polarization response orbitals through dipole and quadrupole perturbation in a water dimer complex, (2) the ground and first excited-state potential energy curves of ethene about its C-C bond rotation, and (3) excitation energies of double electron excited states. Multistate density functional theory is used to determine the energies of the adiabatic ground and excited states using a minimal active space (MAS) comprising specifically charge-constrained and excited determinant configurations that are variationally optimized by the GBLO method. We find that the GBLO expansion that includes delocalized MOs in configurational blocks significantly reduces computational errors in comparison with physical block localization, and the computed ground- and excited-state energies are in good accordance with experiments and results obtained from multireference configuration interaction calculations.

Original languageEnglish (US)
Pages (from-to)277-289
Number of pages13
JournalJournal of Chemical Theory and Computation
Issue number1
StatePublished - Dec 24 2020

Bibliographical note

Funding Information:
This work was supported in part by Shenzhen Municipal Science and Technology Innovation Commission (KQTD2017-0330155106581) and the Ministry of Science and Technology of China (grant number 2017YFB0203400). A.G. is a recipient of an International Postdoctoral Fellowship of China. A.G. would like to thank Dr. Zexing Qu and Ruxin Qu for many helpful discussions.

Publisher Copyright:
© 2020 American Chemical Society.

Copyright 2021 Elsevier B.V., All rights reserved.


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