Vibronic coupling density analysis and quantum dynamics simulation for singlet fission in pentacene and its halogenated derivatives
- 1 October 2020
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 153 (13), 134302
- https://doi.org/10.1063/5.0024746
Abstract
We theoretically investigate microscopic origins of vibronic coupling (VC) contributing to singlet fission (SF) dynamics in pentacene and its halogenated derivatives. The features of VCs related to diabatic exciton states and interstate electronic couplings (Holstein and Peierls couplings, respectively) are interpreted by the VC density (VCD) analysis, which allows one to clarify the relationship between the chemical structure and VC as spatial contribution. It is found for the pentacene dimer face-to-edge configuration in a herringbone crystal that characteristic intermolecular vibrations with low frequencies exhibit strong Holstein couplings for the intermediate charge-transfer (CT) exciton states as well as Peierls couplings. From VCD analysis, the comprising density of the intermolecular CT and that of the intermolecular vibration are found to be constructively mixed in the intermolecular space, leading to the enhancement of VC. Moreover, in order to assess the chemical modification manner for controlling VC, we design several halogenated pentacene derivatives with slip-stack configurations. Our strategy to enhance VCD by halogenation is found to be rational, whereas the peaks of VC spectra for the CT states in the slip-stack packings are observed in high frequency regions. We compare their SF dynamics based on the quantum master equation explicitly including the exciton state-dependent VCs. From the analysis on relative relaxation factors between the adiabatic exciton states, their difference in the SF rate is highlighted by exciton configurations in addition to VCs. The present study is expected to be a first step toward efficient SF based on the design of VC in terms of both the chemical structure and intermolecular packing.Keywords
Funding Information
- Japan Society for the Promotion of Science (JP18H01943, JP20K21173, JP18J20887, JP20J20287)
This publication has 63 references indexed in Scilit:
- Mechanism for Singlet Fission in Pentacene and Tetracene: From Single Exciton to Two TripletsJournal of the American Chemical Society, 2011
- Singlet FissionChemical Reviews, 2010
- A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-PuThe Journal of Chemical Physics, 2010
- Vibronic Coupling in Naphthalene Anion: Vibronic Coupling Density Analysis for Totally Symmetric Vibrational ModesThe Journal of Physical Chemistry A, 2008
- A Polymorph Lost and Found: The High‐Temperature Crystal Structure of PentaceneAdvanced Materials, 2007
- Exciton migration dynamics in a dendritic molecule: Quantum master equation approach using ab initio molecular orbital configuration interaction methodThe Journal of Chemical Physics, 2004
- Mechanism of exciton migration of dendritic molecular aggregate: a master equation approach including weak exciton–phonon couplingChemical Physics Letters, 2002
- IMOMM: A new integrated ab initio + molecular mechanics geometry optimization scheme of equilibrium structures and transition statesJournal of Computational Chemistry, 1995
- UFF, a full periodic table force field for molecular mechanics and molecular dynamics simulationsJournal of the American Chemical Society, 1992
- Development and use of quantum mechanical molecular models. 76. AM1: a new general purpose quantum mechanical molecular modelJournal of the American Chemical Society, 1985