Vibronic Spectra of π-Conjugated Systems with a Multitude of Coupled States: A Protocol Based on Linear Vibronic Coupling Models and Quantum Dynamics Tested on Hexahelicene

2021 ◽  
Vol 17 (3) ◽  
pp. 1691-1700 ◽  
Author(s):  
Daniel Aranda ◽  
Fabrizio Santoro
Keyword(s):  
Quantum Dynamics ◽  
Vibronic Coupling ◽  
Conjugated Systems ◽  
Vibronic Spectra

scholarly journals A Fragment Diabatization Linear Vibronic Coupling Model for Quantum Dynamics of Multichromophoric Systems: Population of the Charge Transfer State in the Photoexcited Guanine Cytosine Pair

2021 ◽  
Author(s):  
James Green ◽  
Martha Yaghoubi Jouybari ◽  
Haritha Asha ◽  
Fabrizio Santoro ◽  
Roberto Improta
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Quantum Dynamics ◽  
Reorganization Energy ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Strongly Coupled ◽  
Exciton Localization ◽  
Td Dft

<div>We introduce a method (FrD-LVC) based on a fragment diabatization (FrD) for the parametrization of a Linear Vibronic Coupling (LVC) model suitable for studying the photophysics of multichromophore systems. In combination with effective quantum dynamics (QD) propagations with multilayer multiconfigurational time-dependent Hartree (ML-MCTDH), the FrD-LVC approach gives access to the study of the competition between intra-chromophore decays, like those at conical intersections, and inter-chromophore processes, like exciton localization/delocalization and the involvement of charge transfer (CT) states. We used FrD-LVC parametrized with TD-DFT calculations, adopting either CAM-B3LYP or ωB97X-D functionals, to study the ultrafast photoexcited QD of a Guanine-Cytosine (GC) hydrogen bonded pair, within a Watson-Crick arrangement, considering up to 12 coupled diabatic electronic states and the effect of all the 99 vibrational coordinates. The bright excited states localized on C and, especially, on G are predicted to be strongly coupled to the G->C CT state which is efficiently and quickly populated after an excitation to any of the four lowest energy bright local excited states. Our QD simulations show that more than 80% of the excited population on G and ~50% of that on C decays to this CT state in less than 50 fs. We investigate the role of vibronic effects in the population of the CT state and show it depends mainly on its large reorganization energy so that it can occur even when it is significantly less stable than the bright states in the Franck-Condon region. At the same time, we document that the formation of the GC pair almost suppresses the involvement of dark nπ* excited states in the photoactivated dynamics.</div>

Competition between the heavy atom effect and vibronic coupling in donor–bridge–acceptor organometallics

2020 ◽  
Vol 22 (8) ◽  
pp. 4659-4667 ◽  
Author(s):  
Julien Eng ◽  
Stuart Thompson ◽  
Heather Goodwin ◽  
Dan Credgington ◽  
Thomas James Penfold
Keyword(s):  
Excited State ◽  
Quantum Dynamics ◽  
Heavy Atom ◽  
Vibronic Coupling ◽  
Intersystem Crossing ◽  
Heavy Atom Effect ◽  
Metal Amides ◽  
Coinage Metals ◽  
Dynamics Simulations ◽  
Atom Effect

The excited state properties and intersystem crossing dynamics of a series of donor–bridge–acceptor carbene metal-amides based upon the coinage metals Cu, Ag, Au, are investigated using quantum dynamics simulations and supported by photophysical characterisation.

Quantum dynamics of Renner–Teller vibronic coupling: The predissociation of HCO

1993 ◽  
Vol 99 (8) ◽  
pp. 5812-5827 ◽  
Author(s):  
Evelyn M. Goldfield ◽  
Stephen K. Gray ◽  
Lawrence B. Harding
Keyword(s):  
Quantum Dynamics ◽  
Vibronic Coupling

scholarly journals Nonadiabatic Absorption Spectra and Ultrafast Dynamics of DNA and RNA Photoexcited Nucleobases

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1743
Author(s):  
James A. Green ◽  
Martha Yaghoubi Jouybari ◽  
Daniel Aranda ◽  
Roberto Improta ◽  
Fabrizio Santoro
Keyword(s):  
Absorption Spectra ◽  
Excited States ◽  
Quantum Dynamics ◽  
Density Functional ◽  
Basis Set ◽  
Ultrafast Dynamics ◽  
Effective Population ◽  
Dna And Rna ◽  
Vibronic Spectra ◽  
Effective Wave

We have recently proposed a protocol for Quantum Dynamics (QD) calculations, which is based on a parameterisation of Linear Vibronic Coupling (LVC) Hamiltonians with Time Dependent (TD) Density Functional Theory (TD-DFT), and exploits the latest developments in multiconfigurational TD-Hartree methods for an effective wave packet propagation. In this contribution we explore the potentialities of this approach to compute nonadiabatic vibronic spectra and ultrafast dynamics, by applying it to the five nucleobases present in DNA and RNA. For all of them we computed the absorption spectra and the dynamics of ultrafast internal conversion (100 fs timescale), fully coupling the first 2–3 bright states and all the close by dark states, for a total of 6–9 states, and including all the normal coordinates. We adopted two different functionals, CAM-B3LYP and PBE0, and tested the effect of the basis set. Computed spectra are in good agreement with the available experimental data, remarkably improving over pure electronic computations, but also with respect to vibronic spectra obtained neglecting inter-state couplings. Our QD simulations indicate an effective population transfer from the lowest energy bright excited states to the close-lying dark excited states for uracil, thymine and adenine. Dynamics from higher-energy states show an ultrafast depopulation toward the more stable ones. The proposed protocol is sufficiently general and automatic to promise to become useful for widespread applications.

Vibronic coupling density analysis and quantum dynamics simulation for singlet fission in pentacene and its halogenated derivatives

2020 ◽  
Vol 153 (13) ◽  
pp. 134302
Author(s):  
Takanori Nagami ◽  
Takayoshi Tonami ◽  
Kenji Okada ◽  
Wataru Yoshida ◽  
Hajime Miyamoto ◽  
...  
Keyword(s):  
Quantum Dynamics ◽  
Vibronic Coupling ◽  
Dynamics Simulation ◽  
Singlet Fission ◽  
Density Analysis

scholarly journals A Fragment Diabatization Linear Vibronic Coupling Model for Quantum Dynamics of Multichromophoric Systems: Population of the Charge Transfer State in the Photoexcited Guanine Cytosine Pair

2021 ◽  
Author(s):  
James Green ◽  
Martha Yaghoubi Jouybari ◽  
Haritha Asha ◽  
Fabrizio Santoro ◽  
Roberto Improta
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Quantum Dynamics ◽  
Reorganization Energy ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Strongly Coupled ◽  
Exciton Localization ◽  
Td Dft

<div>We introduce a method (FrD-LVC) based on a fragment diabatization (FrD) for the parametrization of a Linear Vibronic Coupling (LVC) model suitable for studying the photophysics of multichromophore systems. In combination with effective quantum dynamics (QD) propagations with multilayer multiconfigurational time-dependent Hartree (ML-MCTDH), the FrD-LVC approach gives access to the study of the competition between intra-chromophore decays, like those at conical intersections, and inter-chromophore processes, like exciton localization/delocalization and the involvement of charge transfer (CT) states. We used FrD-LVC parametrized with TD-DFT calculations, adopting either CAM-B3LYP or ωB97X-D functionals, to study the ultrafast photoexcited QD of a Guanine-Cytosine (GC) hydrogen bonded pair, within a Watson-Crick arrangement, considering up to 12 coupled diabatic electronic states and the effect of all the 99 vibrational coordinates. The bright excited states localized on C and, especially, on G are predicted to be strongly coupled to the G->C CT state which is efficiently and quickly populated after an excitation to any of the four lowest energy bright local excited states. Our QD simulations show that more than 80% of the excited population on G and ~50% of that on C decays to this CT state in less than 50 fs. We investigate the role of vibronic effects in the population of the CT state and show it depends mainly on its large reorganization energy so that it can occur even when it is significantly less stable than the bright states in the Franck-Condon region. At the same time, we document that the formation of the GC pair almost suppresses the involvement of dark nπ* excited states in the photoactivated dynamics.</div>

scholarly journals Parameterization of a linear vibronic coupling model with multiconfigurational electronic structure methods to study the quantum dynamics of photoexcited pyrene

2021 ◽  
Vol 154 (10) ◽  
pp. 104106
Author(s):  
Flavia Aleotti ◽  
Daniel Aranda ◽  
Martha Yaghoubi Jouybari ◽  
Marco Garavelli ◽  
Artur Nenov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Quantum Dynamics ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Electronic Structure Methods
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