1.
Rodríguez-Jiménez, José Aarón; Calupitan, Jan Patrick; Casanova, David
Electronic structure origins of radical character in triangular fused acenes: sextet stabilization vs. antiaromaticity release Journal Article
In: Org. Chem. Front., vol. 13, no. 3, pp. 794–802, 2026, ISSN: 2052-4129.
Abstract | Links | BibTeX | Tags: MolEles-KT
@article{Rodríguez-Jiménez2026,
title = {Electronic structure origins of radical character in triangular fused acenes: sextet stabilization \textit{vs.} antiaromaticity release},
author = {José Aarón Rodríguez-Jiménez and Jan Patrick Calupitan and David Casanova},
doi = {10.1039/d5qo01343g},
issn = {2052-4129},
year = {2026},
date = {2026-02-02},
urldate = {2026-02-02},
journal = {Org. Chem. Front.},
volume = {13},
number = {3},
pages = {794--802},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {<jats:p>Triangular acenes display size-dependent radical character arising from the interplay between Clar's sextet stabilization and the release of cyclobutadiene antiaromaticity.</jats:p>},
keywords = {MolEles-KT},
pubstate = {published},
tppubtype = {article}
}
<jats:p>Triangular acenes display size-dependent radical character arising from the interplay between Clar's sextet stabilization and the release of cyclobutadiene antiaromaticity.</jats:p>
2.
Carreras, Abel; Orús, Román; Casanova, David
Limitations of quantum hardware for molecular energy estimation using VQE Journal Article
In: Phys. Chem. Chem. Phys., vol. 28, no. 4, pp. 2834–2846, 2026, ISSN: 1463-9084.
Abstract | Links | BibTeX | Tags: MolEles-KT
@article{Carreras2026,
title = {Limitations of quantum hardware for molecular energy estimation using VQE},
author = {Abel Carreras and Román Orús and David Casanova},
doi = {10.1039/d5cp03907j},
issn = {1463-9084},
year = {2026},
date = {2026-01-28},
urldate = {2026-01-28},
journal = {Phys. Chem. Chem. Phys.},
volume = {28},
number = {4},
pages = {2834--2846},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {<jats:p>In this study, we investigate the performance of VQE algorithms implemented on current quantum hardware for determining molecular ground-state energies, focusing on the adaptive derivative-assembled pseudo-Trotter ansatz VQE (ADAPT-VQE).</jats:p>},
keywords = {MolEles-KT},
pubstate = {published},
tppubtype = {article}
}
<jats:p>In this study, we investigate the performance of VQE algorithms implemented on current quantum hardware for determining molecular ground-state energies, focusing on the adaptive derivative-assembled pseudo-Trotter ansatz VQE (ADAPT-VQE).</jats:p>
3.
Omist, Alicia; Casanova, David
Spin-Permutation Diabatization: A General Framework for Spin Localization and Exchange Coupling Journal Article
In: J. Chem. Theory Comput., vol. 22, no. 2, pp. 963–971, 2026, ISSN: 1549-9626.
Links | BibTeX | Tags: MolEles-KT
@article{Omist2026,
title = {Spin-Permutation Diabatization: A General Framework for Spin Localization and Exchange Coupling},
author = {Alicia Omist and David Casanova},
doi = {10.1021/acs.jctc.5c01904},
issn = {1549-9626},
year = {2026},
date = {2026-01-27},
urldate = {2026-01-27},
journal = {J. Chem. Theory Comput.},
volume = {22},
number = {2},
pages = {963--971},
publisher = {American Chemical Society (ACS)},
keywords = {MolEles-KT},
pubstate = {published},
tppubtype = {article}
}
4.
Manjanath, Aaditya; Casanova, David; Sahara, Ryoji; Hsu, Chao‐Ping
Localized Molecular Orbitals for Single Excitation Theories Journal Article
In: J Comput Chem, vol. 47, no. 1, 2026, ISSN: 1096-987X.
Abstract | Links | BibTeX | Tags: MolEles-KT
@article{Manjanath2025,
title = {Localized Molecular Orbitals for Single Excitation Theories},
author = {Aaditya Manjanath and David Casanova and Ryoji Sahara and Chao‐Ping Hsu},
doi = {10.1002/jcc.70293},
issn = {1096-987X},
year = {2026},
date = {2026-01-05},
urldate = {2026-01-05},
journal = {J Comput Chem},
volume = {47},
number = {1},
publisher = {Wiley},
abstract = {<jats:title>ABSTRACT</jats:title>
<jats:p>Excited states of systems composed of linked fragments or stacked molecules are important for understanding their optoelectronic properties. These states, when projected to individual fragments, are either local (LEs) or charge transfer excitons (CTEs). However, the canonical molecular orbitals (CMOs) obtained from a typical calculation tend to delocalize, which makes the subsequent analysis of excited states cumbersome. In this work, we report a simple approach to address this problem by employing localized molecular orbitals (LMOs) as linear combinations of the CMOs in the occupied and virtual subspaces separately after a self‐consistent field calculation. This separated linear combination ensures that configuration interaction singles (CIS), random phase approximation (RPA), and their corresponding density functional theory (DFT) counterparts [Tamm‐Dancoff approximation time‐dependent DFT (TDA‐TDDFT) and TDDFT] calculations with LMOs are mathematically equivalent to those performed with CMOs. We performed tests on simple symmetric and asymmetric dimer systems and found that the excited states are numerically identical in excitation energies and transition moments for both LMOs and CMOs, except for very few states that are only found in either LMO or CMO (in symmetric cases). The LMO basis makes both qualitative and quantitative analyses of the excited states much more accessible, as the extent of LE and CTE contributions can be easily defined. Consequently, this simple yet robust approach can be useful for characterizing excitons in multichromophoric systems and in condensed phases, which is useful when studying problems pertaining to electron/excitation energy transfer processes.</jats:p>},
keywords = {MolEles-KT},
pubstate = {published},
tppubtype = {article}
}
<jats:title>ABSTRACT</jats:title>
<jats:p>Excited states of systems composed of linked fragments or stacked molecules are important for understanding their optoelectronic properties. These states, when projected to individual fragments, are either local (LEs) or charge transfer excitons (CTEs). However, the canonical molecular orbitals (CMOs) obtained from a typical calculation tend to delocalize, which makes the subsequent analysis of excited states cumbersome. In this work, we report a simple approach to address this problem by employing localized molecular orbitals (LMOs) as linear combinations of the CMOs in the occupied and virtual subspaces separately after a self‐consistent field calculation. This separated linear combination ensures that configuration interaction singles (CIS), random phase approximation (RPA), and their corresponding density functional theory (DFT) counterparts [Tamm‐Dancoff approximation time‐dependent DFT (TDA‐TDDFT) and TDDFT] calculations with LMOs are mathematically equivalent to those performed with CMOs. We performed tests on simple symmetric and asymmetric dimer systems and found that the excited states are numerically identical in excitation energies and transition moments for both LMOs and CMOs, except for very few states that are only found in either LMO or CMO (in symmetric cases). The LMO basis makes both qualitative and quantitative analyses of the excited states much more accessible, as the extent of LE and CTE contributions can be easily defined. Consequently, this simple yet robust approach can be useful for characterizing excitons in multichromophoric systems and in condensed phases, which is useful when studying problems pertaining to electron/excitation energy transfer processes.</jats:p>
<jats:p>Excited states of systems composed of linked fragments or stacked molecules are important for understanding their optoelectronic properties. These states, when projected to individual fragments, are either local (LEs) or charge transfer excitons (CTEs). However, the canonical molecular orbitals (CMOs) obtained from a typical calculation tend to delocalize, which makes the subsequent analysis of excited states cumbersome. In this work, we report a simple approach to address this problem by employing localized molecular orbitals (LMOs) as linear combinations of the CMOs in the occupied and virtual subspaces separately after a self‐consistent field calculation. This separated linear combination ensures that configuration interaction singles (CIS), random phase approximation (RPA), and their corresponding density functional theory (DFT) counterparts [Tamm‐Dancoff approximation time‐dependent DFT (TDA‐TDDFT) and TDDFT] calculations with LMOs are mathematically equivalent to those performed with CMOs. We performed tests on simple symmetric and asymmetric dimer systems and found that the excited states are numerically identical in excitation energies and transition moments for both LMOs and CMOs, except for very few states that are only found in either LMO or CMO (in symmetric cases). The LMO basis makes both qualitative and quantitative analyses of the excited states much more accessible, as the extent of LE and CTE contributions can be easily defined. Consequently, this simple yet robust approach can be useful for characterizing excitons in multichromophoric systems and in condensed phases, which is useful when studying problems pertaining to electron/excitation energy transfer processes.</jats:p>