Clustered Graph Partitions Provide Compact Diabatic Bases for RCI-LC-DFTB Charge-Transfer Calculations
Abstract
Restriction-based configuration interaction long-range corrected self-consistent charge density functional tight binding (RCI-LC-DFTB) is an efficient approximate quantum chemical method that uses non-orthogonal diabatic states to describe molecular chargetransfer states. However, its practical performance depends on how the charge-localized diabatic states are selected. Here, we develop and compare two graph-based strategies for automated diabatic-basis construction: a discrete graph Fourier representation and a clustered biconnected-partition representation. Applications to benzene-assembly benchmark systems show that the discrete graph Fourier representation provides a systematic expansion that can require many diabatic states, whereas the clustered biconnected- partition representation gives a more compact and chemically interpretable basis. We further apply the clustered representation to a 16-residue aromatic oligoamide foldamer under an external electric field, demonstrating unit-resolved analysis of field-induced long-range charge localization. These results show that clustered graph partitions
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BibTeX
@misc{huang2026clustered,
title = {{Clustered Graph Partitions Provide Compact Diabatic Bases for RCI-LC-DFTB Charge-Transfer Calculations}},
author = {Ji Huang and Tim Kowalczyk and Daisuke Yokogawa},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008502/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008502/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Clustered Graph Partitions Provide Compact Diabatic Bases for RCI-LC-DFTB Charge-Transfer Calculations
AU - Ji Huang
AU - Tim Kowalczyk
AU - Daisuke Yokogawa
PY - 2026
DA - 2026/09/08
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008502/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008502/v1
AB - Restriction-based configuration interaction long-range corrected self-consistent charge density functional tight binding (RCI-LC-DFTB) is an efficient approximate quantum chemical method that uses non-orthogonal diabatic states to describe molecular chargetransfer states. However, its practical performance depends on how the charge-localized diabatic states are selected. Here, we develop and compare two graph-based strategies for automated diabatic-basis construction: a discrete graph Fourier representation and a clustered biconnected-partition representation. Applications to benzene-assembly benchmark systems show that the discrete graph Fourier representation provides a systematic expansion that can require many diabatic states, whereas the clustered biconnected- partition representation gives a more compact and chemically interpretable basis. We further apply the clustered representation to a 16-residue aromatic oligoamide foldamer under an external electric field, demonstrating unit-resolved analysis of field-induced long-range charge localization. These results show that clustered graph partitions
ER -