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Title: Comments on the optical lineshape function: Application to transient hole-burned spectra of bacterial reaction centers

Abstract

The vibrational spectral density is an important physical parameter needed to describe both linear and non-linear spectra of multi-chromophore systems such as photosynthetic complexes. Low-temperature techniques such as hole burning (HB) and fluorescence line narrowing are commonly used to extract the spectral density for a given electronic transition from experimental data. We report here that the lineshape function formula reported by Hayes et al. [J. Phys. Chem. 98, 7337 (1994)] in the mean-phonon approximation and frequently applied to analyzing HB data contains inconsistencies in notation, leading to essentially incorrect expressions in cases of moderate and strong electron-phonon (el-ph) coupling strengths. A corrected lineshape function L(ω) is given that retains the computational and intuitive advantages of the expression of Hayes et al. [J. Phys. Chem. 98, 7337 (1994)]. Although the corrected lineshape function could be used in modeling studies of various optical spectra, we suggest that it is better to calculate the lineshape function numerically, without introducing the mean-phonon approximation. New theoretical fits of the P870 and P960 absorption bands and frequency-dependent resonant HB spectra of Rb. sphaeroides and Rps. viridis reaction centers are provided as examples to demonstrate the importance of correct lineshape expressions. Comparison with the previously determined el-phmore » coupling parameters [Johnson et al., J. Phys. Chem. 94, 5849 (1990); Lyle et al., ibid. 97, 6924 (1993); Reddy et al., ibid. 97, 6934 (1993)] is also provided. The new fits lead to modified el-ph coupling strengths and different frequencies of the special pair marker mode, ω{sub sp}, for Rb. sphaeroides that could be used in the future for more advanced calculations of absorption and HB spectra obtained for various bacterial reaction centers.« less

Authors:
; ;  [1];  [1]
  1. Department of Chemistry, Kansas State University, Manhattan, Kansas 66506 (United States)
Publication Date:
OSTI Identifier:
22416207
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; APPROXIMATIONS; COMPARATIVE EVALUATIONS; COMPLEXES; COUPLING; ELECTRONS; FLUORESCENCE; FREQUENCY DEPENDENCE; HOLES; LINE NARROWING; NONLINEAR PROBLEMS; PH VALUE; PHONONS; PHOTOSYNTHESIS; SPECTRA; SPECTRAL DENSITY; TEMPERATURE DEPENDENCE; TRANSIENTS

Citation Formats

Reppert, Mike, Kell, Adam, Pruitt, Thomas, Jankowiak, Ryszard, and Department of Physics, Kansas State University, Manhattan, Kansas 66506. Comments on the optical lineshape function: Application to transient hole-burned spectra of bacterial reaction centers. United States: N. p., 2015. Web. doi:10.1063/1.4913685.
Reppert, Mike, Kell, Adam, Pruitt, Thomas, Jankowiak, Ryszard, & Department of Physics, Kansas State University, Manhattan, Kansas 66506. Comments on the optical lineshape function: Application to transient hole-burned spectra of bacterial reaction centers. United States. https://doi.org/10.1063/1.4913685
Reppert, Mike, Kell, Adam, Pruitt, Thomas, Jankowiak, Ryszard, and Department of Physics, Kansas State University, Manhattan, Kansas 66506. 2015. "Comments on the optical lineshape function: Application to transient hole-burned spectra of bacterial reaction centers". United States. https://doi.org/10.1063/1.4913685.
@article{osti_22416207,
title = {Comments on the optical lineshape function: Application to transient hole-burned spectra of bacterial reaction centers},
author = {Reppert, Mike and Kell, Adam and Pruitt, Thomas and Jankowiak, Ryszard and Department of Physics, Kansas State University, Manhattan, Kansas 66506},
abstractNote = {The vibrational spectral density is an important physical parameter needed to describe both linear and non-linear spectra of multi-chromophore systems such as photosynthetic complexes. Low-temperature techniques such as hole burning (HB) and fluorescence line narrowing are commonly used to extract the spectral density for a given electronic transition from experimental data. We report here that the lineshape function formula reported by Hayes et al. [J. Phys. Chem. 98, 7337 (1994)] in the mean-phonon approximation and frequently applied to analyzing HB data contains inconsistencies in notation, leading to essentially incorrect expressions in cases of moderate and strong electron-phonon (el-ph) coupling strengths. A corrected lineshape function L(ω) is given that retains the computational and intuitive advantages of the expression of Hayes et al. [J. Phys. Chem. 98, 7337 (1994)]. Although the corrected lineshape function could be used in modeling studies of various optical spectra, we suggest that it is better to calculate the lineshape function numerically, without introducing the mean-phonon approximation. New theoretical fits of the P870 and P960 absorption bands and frequency-dependent resonant HB spectra of Rb. sphaeroides and Rps. viridis reaction centers are provided as examples to demonstrate the importance of correct lineshape expressions. Comparison with the previously determined el-ph coupling parameters [Johnson et al., J. Phys. Chem. 94, 5849 (1990); Lyle et al., ibid. 97, 6924 (1993); Reddy et al., ibid. 97, 6934 (1993)] is also provided. The new fits lead to modified el-ph coupling strengths and different frequencies of the special pair marker mode, ω{sub sp}, for Rb. sphaeroides that could be used in the future for more advanced calculations of absorption and HB spectra obtained for various bacterial reaction centers.},
doi = {10.1063/1.4913685},
url = {https://www.osti.gov/biblio/22416207}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 9,
volume = 142,
place = {United States},
year = {Sat Mar 07 00:00:00 EST 2015},
month = {Sat Mar 07 00:00:00 EST 2015}
}