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Title: Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model

Abstract

Subsystem density-functional theory (DFT) is a powerful and efficient alternative to Kohn-Sham DFT for large systems composed of several weakly interacting subunits. Here, we provide a systematic investigation of the spin-density distributions obtained in subsystem DFT calculations for radicals in explicit environments. This includes a small radical in a solvent shell, a {pi}-stacked guanine-thymine radical cation, and a benchmark application to a model for the special pair radical cation, which is a dimer of bacteriochlorophyll pigments, from the photosynthetic reaction center of purple bacteria. We investigate the differences in the spin densities resulting from subsystem DFT and Kohn-Sham DFT calculations. In these comparisons, we focus on the problem of overdelocalization of spin densities due to the self-interaction error in DFT. It is demonstrated that subsystem DFT can reduce this problem, while it still allows to describe spin-polarization effects crossing the boundaries of the subsystems. In practical calculations of spin densities for radicals in a given environment, it may thus be a pragmatic alternative to Kohn-Sham DFT calculations. In our calculation on the special pair radical cation, we show that the coordinating histidine residues reduce the spin-density asymmetry between the two halves of this system, while inclusion of a larger bindingmore » pocket model increases this asymmetry. The unidirectional energy transfer in photosynthetic reaction centers is related to the asymmetry introduced by the protein environment.« less

Authors:
 [1];  [1];  [2]
  1. Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)
  2. Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)
Publication Date:
OSTI Identifier:
22047210
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 136; Journal Issue: 19; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 60 APPLIED LIFE SCIENCES; ASYMMETRY; BACTERIA; CATIONS; DENSITY; DENSITY FUNCTIONAL METHOD; GUANINE; HISTIDINE; PHOTOSYNTHESIS; PHOTOSYNTHETIC REACTION CENTERS; PROTEINS; RADICALS; SPIN; SPIN ORIENTATION; THYMINE

Citation Formats

Solovyeva, Alisa, Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig, Pavanello, Michele, and Neugebauer, Johannes. Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model. United States: N. p., 2012. Web. doi:10.1063/1.4709771.
Solovyeva, Alisa, Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig, Pavanello, Michele, & Neugebauer, Johannes. Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model. United States. https://doi.org/10.1063/1.4709771
Solovyeva, Alisa, Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig, Pavanello, Michele, and Neugebauer, Johannes. 2012. "Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model". United States. https://doi.org/10.1063/1.4709771.
@article{osti_22047210,
title = {Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model},
author = {Solovyeva, Alisa and Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig and Pavanello, Michele and Neugebauer, Johannes},
abstractNote = {Subsystem density-functional theory (DFT) is a powerful and efficient alternative to Kohn-Sham DFT for large systems composed of several weakly interacting subunits. Here, we provide a systematic investigation of the spin-density distributions obtained in subsystem DFT calculations for radicals in explicit environments. This includes a small radical in a solvent shell, a {pi}-stacked guanine-thymine radical cation, and a benchmark application to a model for the special pair radical cation, which is a dimer of bacteriochlorophyll pigments, from the photosynthetic reaction center of purple bacteria. We investigate the differences in the spin densities resulting from subsystem DFT and Kohn-Sham DFT calculations. In these comparisons, we focus on the problem of overdelocalization of spin densities due to the self-interaction error in DFT. It is demonstrated that subsystem DFT can reduce this problem, while it still allows to describe spin-polarization effects crossing the boundaries of the subsystems. In practical calculations of spin densities for radicals in a given environment, it may thus be a pragmatic alternative to Kohn-Sham DFT calculations. In our calculation on the special pair radical cation, we show that the coordinating histidine residues reduce the spin-density asymmetry between the two halves of this system, while inclusion of a larger binding pocket model increases this asymmetry. The unidirectional energy transfer in photosynthetic reaction centers is related to the asymmetry introduced by the protein environment.},
doi = {10.1063/1.4709771},
url = {https://www.osti.gov/biblio/22047210}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 19,
volume = 136,
place = {United States},
year = {Mon May 21 00:00:00 EDT 2012},
month = {Mon May 21 00:00:00 EDT 2012}
}