Absorption-emission symmetry breaking and the different origins of vibrational structures of the 1Qy and 1Qx electronic transitions of pheophytin a

Rätsep, M; Linnanto, JM; Muru, R; Biczysko, M; Reimers, JR; Freiberg, A

Absorption-emission symmetry breaking and the different origins of vibrational structures of the 1Qy and 1Qx electronic transitions of pheophytin a

Rätsep, M Linnanto, JM Muru, R Biczysko, M Reimers, JR

Freiberg, A

Permalink

Publication Type:: Journal Article
Citation:: Journal of Chemical Physics, 2019, 151 (16)
Issue Date:: 2019-10-28

Open Access

Copyright Clearance Process

Recently Added
In Progress
Open Access

This item is open access.

Adobe PDF

Download Published VersionAdobe PDF (2.5 MB)

View on publisher's site

View statistics

Full metadata record

Field	Value	Language
dc.contributor.author	Rätsep, M	en_US
dc.contributor.author	Linnanto, JM	en_US
dc.contributor.author	Muru, R	en_US
dc.contributor.author	Biczysko, M	en_US
dc.contributor.author	Reimers, JR https://orcid.org/0000-0001-5157-7422	en_US
dc.contributor.author	Freiberg, A	en_US
dc.date.available	2020-11-01T18:01:56Z
dc.date.issued	2019-10-28	en_US
dc.identifier.citation	Journal of Chemical Physics, 2019, 151 (16)	en_US
dc.identifier.issn	0021-9606	en_US
dc.identifier.uri	http://hdl.handle.net/10453/136753
dc.description.abstract	© 2019 Author(s). The vibrational structure of the optical absorption and fluorescence spectra of the two lowest-energy singlet electronic states (Qy and Qx) of pheophytin a were carefully studied by combining low-resolution and high-resolution spectroscopy with quantum chemical analysis and spectral modeling. Large asymmetry was revealed between the vibrational structures of the Qy absorption and fluorescence spectra, integrally characterized by the total Huang-Rhys factor and reorganization energy in absorption of SvibA = 0.43 ± 0.06, λA = 395 cm-1 and in emission of SvibE = 0.35 ± 0.06, λE = 317 cm-1. Time-dependent density-functional theory using the CAM-B3LYP, ωB97XD, and MN15 functionals could predict and interpret this asymmetry, with the exception of one vibrational mode per model, which was badly misrepresented in predicted absorption spectra; for CAM-B3LYP and ωB97XD, this mode was a Kekulé-type mode depicting aromaticity. Other computational methods were also considered but performed very poorly. The Qx absorption spectrum is broad and could not be interpreted in terms of a single set of Huang-Rhys factors depicting Franck-Condon allowed absorption, with Herzberg-Teller contributions to the intensity being critical. For it, CAM-B3LYP calculations predict that SvibA (for modes >100 cm-1) = 0.87 and λA = 780 cm-1, with effective x and y polarized Herzberg-Teller reorganization energies of 460 cm-1 and 210 cm-1, respectively, delivering 15% y-polarized intensity. However, no method was found to quantitatively determine the observed y-polarized contribution, with contributions of up to 50% being feasible.	en_US
dc.relation	http://purl.org/au-research/grants/arc/DP150103137
dc.relation.ispartof	Journal of Chemical Physics	en_US
dc.relation.isbasedon	10.1063/1.5116265	en_US
dc.rights	info:eu-repo/semantics/openAccess
dc.subject.classification	Chemical Physics	en_US
dc.title	Absorption-emission symmetry breaking and the different origins of vibrational structures of the 1Qy and 1Qx electronic transitions of pheophytin a	en_US
dc.type	Journal Article
utslib.citation.volume	16	en_US
utslib.citation.volume	151	en_US
utslib.for	0206 Quantum Physics	en_US
utslib.for	02 Physical Sciences	en_US
utslib.for	03 Chemical Sciences	en_US
utslib.for	09 Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	open_access	*
pubs.issue	16	en_US
pubs.publication-status	Published	en_US
pubs.volume	151	en_US

Abstract:

© 2019 Author(s). The vibrational structure of the optical absorption and fluorescence spectra of the two lowest-energy singlet electronic states (Qy and Qx) of pheophytin a were carefully studied by combining low-resolution and high-resolution spectroscopy with quantum chemical analysis and spectral modeling. Large asymmetry was revealed between the vibrational structures of the Qy absorption and fluorescence spectra, integrally characterized by the total Huang-Rhys factor and reorganization energy in absorption of SvibA = 0.43 ± 0.06, λA = 395 cm-1 and in emission of SvibE = 0.35 ± 0.06, λE = 317 cm-1. Time-dependent density-functional theory using the CAM-B3LYP, ωB97XD, and MN15 functionals could predict and interpret this asymmetry, with the exception of one vibrational mode per model, which was badly misrepresented in predicted absorption spectra; for CAM-B3LYP and ωB97XD, this mode was a Kekulé-type mode depicting aromaticity. Other computational methods were also considered but performed very poorly. The Qx absorption spectrum is broad and could not be interpreted in terms of a single set of Huang-Rhys factors depicting Franck-Condon allowed absorption, with Herzberg-Teller contributions to the intensity being critical. For it, CAM-B3LYP calculations predict that SvibA (for modes >100 cm-1) = 0.87 and λA = 780 cm-1, with effective x and y polarized Herzberg-Teller reorganization energies of 460 cm-1 and 210 cm-1, respectively, delivering 15% y-polarized intensity. However, no method was found to quantitatively determine the observed y-polarized contribution, with contributions of up to 50% being feasible.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/136753