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Updated: Apr 5, 2026
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Restricted and unrestricted non-Hermitian Hartree-Fock: Theory, practical considerations, and applications to
Alec F White1, C William McCurdy2, Martin Head-Gordon3
1Department of Chemistry, Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Abstract:
This work describes the implementation and applications of non-Hermitian self-consistent field (NH-SCF) theory with complex basis functions for the ab initio computation of positions and widths of shape resonances in molecules. We utilize both the restricted open-shell and the previously unexplored spin-unrestricted variants to compute Siegert energies of several anionic shape resonances in small diatomic and polyatomic molecules including carbon tetrafluoride which has been the subject of several recent experimental studies. The computation of general molecular properties from a non-Hermitian wavefunction is discussed, and a density-based analysis is applied to the (2)B1 shape resonance in formaldehyde. Spin-unrestricted NH-SCF is used to compute a complex potential energy surface for the carbon monoxide anion which correctly describes dissociation.
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