Efficient and reliable modeling of large $π$-electron systems with the Pariser--Parr--Pople Hamiltonian and pCCD-based methods
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866916918469853184 |
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| author | Karimi, Zahra Ahmadkhani, Somayeh Boguslawski, Katharina Tecmer, Paweł |
| author_facet | Karimi, Zahra Ahmadkhani, Somayeh Boguslawski, Katharina Tecmer, Paweł |
| contents | Model Hamiltonians offer a cost-effective way to capture the key physics of large $π$-conjugated systems. In this work, we combine the Pariser--Parr--Pople (PPP) model Hamiltonian with pair Coupled Cluster Doubles (pCCD)-based methods to study the ground- and excited-state electronic structures of polycyclic aromatic hydrocarbons (PAHs). The model Hamiltonian implementation is done in the open-source PyBEST software package, where numerous pCCD-type models are available. We investigate canonical Hartree--Fock and natural pCCD-optimized orbitals to compute ground- and excited-state properties using pCCD and its linear response extension. Their performance is compared with configuration-interaction-based methods. Finally, we introduce a generalized parameterization of the long-range Coulomb interaction using a rescaled interaction prefactor to adopt the PPP parameters to the pCCD approach and the localized nature of the pCCD orbitals. Our results demonstrate that pCCD-based methods, combined with a suitably parametrized PPP model, provide a reliable and scalable framework for studying the optoelectronic properties of large $π$-extended systems relevant to organic electronics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_18963 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Efficient and reliable modeling of large $π$-electron systems with the Pariser--Parr--Pople Hamiltonian and pCCD-based methods Karimi, Zahra Ahmadkhani, Somayeh Boguslawski, Katharina Tecmer, Paweł Chemical Physics Model Hamiltonians offer a cost-effective way to capture the key physics of large $π$-conjugated systems. In this work, we combine the Pariser--Parr--Pople (PPP) model Hamiltonian with pair Coupled Cluster Doubles (pCCD)-based methods to study the ground- and excited-state electronic structures of polycyclic aromatic hydrocarbons (PAHs). The model Hamiltonian implementation is done in the open-source PyBEST software package, where numerous pCCD-type models are available. We investigate canonical Hartree--Fock and natural pCCD-optimized orbitals to compute ground- and excited-state properties using pCCD and its linear response extension. Their performance is compared with configuration-interaction-based methods. Finally, we introduce a generalized parameterization of the long-range Coulomb interaction using a rescaled interaction prefactor to adopt the PPP parameters to the pCCD approach and the localized nature of the pCCD orbitals. Our results demonstrate that pCCD-based methods, combined with a suitably parametrized PPP model, provide a reliable and scalable framework for studying the optoelectronic properties of large $π$-extended systems relevant to organic electronics. |
| title | Efficient and reliable modeling of large $π$-electron systems with the Pariser--Parr--Pople Hamiltonian and pCCD-based methods |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2508.18963 |