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Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods

[Image: see text] The ability to accurately compute low-energy excited states of chlorophylls is critically important for understanding the vital roles they play in light harvesting, energy transfer, and photosynthetic charge separation. The challenge for quantum chemical methods arises both from th...

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Autores principales: Sirohiwal, Abhishek, Berraud-Pache, Romain, Neese, Frank, Izsák, Róbert, Pantazis, Dimitrios A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2020
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7584356/
https://www.ncbi.nlm.nih.gov/pubmed/32930590
http://dx.doi.org/10.1021/acs.jpcb.0c05761
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author Sirohiwal, Abhishek
Berraud-Pache, Romain
Neese, Frank
Izsák, Róbert
Pantazis, Dimitrios A.
author_facet Sirohiwal, Abhishek
Berraud-Pache, Romain
Neese, Frank
Izsák, Róbert
Pantazis, Dimitrios A.
author_sort Sirohiwal, Abhishek
collection PubMed
description [Image: see text] The ability to accurately compute low-energy excited states of chlorophylls is critically important for understanding the vital roles they play in light harvesting, energy transfer, and photosynthetic charge separation. The challenge for quantum chemical methods arises both from the intrinsic complexity of the electronic structure problem and, in the case of biological models, from the need to account for protein–pigment interactions. In this work, we report electronic structure calculations of unprecedented accuracy for the low-energy excited states in the Q and B bands of chlorophyll a. This is achieved by using the newly developed domain-based local pair natural orbital (DLPNO) implementation of the similarity transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD) in combination with sufficiently large and flexible basis sets. The results of our DLPNO–STEOM-CCSD calculations are compared with more approximate approaches. The results demonstrate that, in contrast to time-dependent density functional theory, the DLPNO–STEOM-CCSD method provides a balanced performance for both absorption bands. In addition to vertical excitation energies, we have calculated the vibronic spectrum for the Q and B bands through a combination of DLPNO–STEOM-CCSD and ground-state density functional theory frequency calculations. These results serve as a basis for comparison with gas-phase experiments.
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spelling pubmed-75843562020-10-26 Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods Sirohiwal, Abhishek Berraud-Pache, Romain Neese, Frank Izsák, Róbert Pantazis, Dimitrios A. J Phys Chem B [Image: see text] The ability to accurately compute low-energy excited states of chlorophylls is critically important for understanding the vital roles they play in light harvesting, energy transfer, and photosynthetic charge separation. The challenge for quantum chemical methods arises both from the intrinsic complexity of the electronic structure problem and, in the case of biological models, from the need to account for protein–pigment interactions. In this work, we report electronic structure calculations of unprecedented accuracy for the low-energy excited states in the Q and B bands of chlorophyll a. This is achieved by using the newly developed domain-based local pair natural orbital (DLPNO) implementation of the similarity transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD) in combination with sufficiently large and flexible basis sets. The results of our DLPNO–STEOM-CCSD calculations are compared with more approximate approaches. The results demonstrate that, in contrast to time-dependent density functional theory, the DLPNO–STEOM-CCSD method provides a balanced performance for both absorption bands. In addition to vertical excitation energies, we have calculated the vibronic spectrum for the Q and B bands through a combination of DLPNO–STEOM-CCSD and ground-state density functional theory frequency calculations. These results serve as a basis for comparison with gas-phase experiments. American Chemical Society 2020-09-15 2020-10-08 /pmc/articles/PMC7584356/ /pubmed/32930590 http://dx.doi.org/10.1021/acs.jpcb.0c05761 Text en This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
spellingShingle Sirohiwal, Abhishek
Berraud-Pache, Romain
Neese, Frank
Izsák, Róbert
Pantazis, Dimitrios A.
Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title_full Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title_fullStr Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title_full_unstemmed Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title_short Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods
title_sort accurate computation of the absorption spectrum of chlorophyll a with pair natural orbital coupled cluster methods
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7584356/
https://www.ncbi.nlm.nih.gov/pubmed/32930590
http://dx.doi.org/10.1021/acs.jpcb.0c05761
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