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Title: Photoinduced non-adiabatic energy transfer pathways in dendrimer building blocks

Abstract

The efficiency of the intramolecular energy transfer in light harvesting dendrimers is determined by their well-defined architecture with high degree of order. After photoexcitation, through-space and through-bond energy transfer mechanisms can take place, involving vectorial exciton migration among different chromophores within dendrimer highly branched structures. Their inherent intramolecular energy gradient depends on how the multiple chromophoric units have been assembled, subject to their inter-connects, spatial distances, and orientations. Herein, we compare the photoinduced nonadiabatic molecular dynamics simulations performed on a set of different combinations of a chain of linked dendrimer building blocks composed of two-, three-, and four-ring linear polyphenylene chromophoric units. The calculations are performed with the recently developed ab initio multiple cloning-time dependent diabatic basis implementation of the Multiconfigurational Ehrenfest (MCE) approach. Despite differences in short time relaxation pathways and different initial exciton localization, at longer time scales, electronic relaxation rates and exciton final redistributions are very similar for all combinations. Unlike the systems composed of two building blocks, considered previously, for the larger 3 block systems here we observe that bifurcation of the wave function accounted by cloning is important. In all the systems considered in this work, at the time scale of few hundreds of femtoseconds,more » cloning enhances the electronic energy relaxation by ~13% compared to that of the MCE method without cloning. Thus, accurate description of quantum effects is essential for understanding of the energy exchange in dendrimers both at short and long time scales.« less

Authors:
 [1];  [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [1]
  1. Univ. Nacional de Quilmes/CONICET, Bernal (Argentina)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of Leeds, Leeds (United Kingdom); Univ. of Bristol, Bristol (United Kingdom)
  4. Univ. of Leeds, Leeds (United Kingdom)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1511627
Alternate Identifier(s):
OSTI ID: 1503378
Report Number(s):
LA-UR-18-31806
Journal ID: ISSN 0021-9606
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 150; Journal Issue: 12; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Freixas, Victor M., Ondarse-Alvarez, Daneilis, Tretiak, Sergei, Makhov, Dmitry V., Shalashilin, Dmitry V., and Fernandez-Alberti, Sebastian. Photoinduced non-adiabatic energy transfer pathways in dendrimer building blocks. United States: N. p., 2019. Web. doi:10.1063/1.5086680.
Freixas, Victor M., Ondarse-Alvarez, Daneilis, Tretiak, Sergei, Makhov, Dmitry V., Shalashilin, Dmitry V., & Fernandez-Alberti, Sebastian. Photoinduced non-adiabatic energy transfer pathways in dendrimer building blocks. United States. doi:10.1063/1.5086680.
Freixas, Victor M., Ondarse-Alvarez, Daneilis, Tretiak, Sergei, Makhov, Dmitry V., Shalashilin, Dmitry V., and Fernandez-Alberti, Sebastian. Mon . "Photoinduced non-adiabatic energy transfer pathways in dendrimer building blocks". United States. doi:10.1063/1.5086680. https://www.osti.gov/servlets/purl/1511627.
@article{osti_1511627,
title = {Photoinduced non-adiabatic energy transfer pathways in dendrimer building blocks},
author = {Freixas, Victor M. and Ondarse-Alvarez, Daneilis and Tretiak, Sergei and Makhov, Dmitry V. and Shalashilin, Dmitry V. and Fernandez-Alberti, Sebastian},
abstractNote = {The efficiency of the intramolecular energy transfer in light harvesting dendrimers is determined by their well-defined architecture with high degree of order. After photoexcitation, through-space and through-bond energy transfer mechanisms can take place, involving vectorial exciton migration among different chromophores within dendrimer highly branched structures. Their inherent intramolecular energy gradient depends on how the multiple chromophoric units have been assembled, subject to their inter-connects, spatial distances, and orientations. Herein, we compare the photoinduced nonadiabatic molecular dynamics simulations performed on a set of different combinations of a chain of linked dendrimer building blocks composed of two-, three-, and four-ring linear polyphenylene chromophoric units. The calculations are performed with the recently developed ab initio multiple cloning-time dependent diabatic basis implementation of the Multiconfigurational Ehrenfest (MCE) approach. Despite differences in short time relaxation pathways and different initial exciton localization, at longer time scales, electronic relaxation rates and exciton final redistributions are very similar for all combinations. Unlike the systems composed of two building blocks, considered previously, for the larger 3 block systems here we observe that bifurcation of the wave function accounted by cloning is important. In all the systems considered in this work, at the time scale of few hundreds of femtoseconds, cloning enhances the electronic energy relaxation by ~13% compared to that of the MCE method without cloning. Thus, accurate description of quantum effects is essential for understanding of the energy exchange in dendrimers both at short and long time scales.},
doi = {10.1063/1.5086680},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 12,
volume = 150,
place = {United States},
year = {2019},
month = {3}
}

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