Theoretical Investigation of Perylene Dimers and Excimers and Their Signatures in X-Ray Diffraction

Velardez, Gustavo F.; Lemke, Henrik T.; Breiby, Dag W.; Nielsen, Martin Meedom; Møller, Klaus Braagaard; Henriksen, Niels Engholm

doi:10.1021/jp8016375

Cited by 18 publications

(35 citation statements)

References 51 publications

(108 reference statements)

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“…The study takes advantage of the recent improvements in DFT/TDDFT functionals to revisit and extend previous theoretical studies on perylene. In addition to reaffirm, complete or correct previous computational results obtained for the perylene monomer [5b] and dimer species, and the present work also explores some unsolved issues, such as relative stability of several dimer conformations beyond the perfectly eclipsed disposition, interpretation of the absorption spectrum in concentrated solution, or the study of higher excited states of the dimer.…”

Section: Introductionsupporting

confidence: 57%

Theoretical investigations of the perylene electronic structure: Monomer, dimers, and excimers

Casanova

2015

Int. J. Quantum Chem.

105

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The structural and electronic properties of perylene molecule, dimers, and excimers have been computationally studied. The present work represents the first systematic study of perylene molecule and dimer forms by means of long‐range corrected time‐dependent density functional theory (TDDFT) approaches. Initially, the study explores the photophysical properties of the molecular species. Vertical transitions to many excited singlet states have been computed and rationalized with different exchange‐correlation functionals. Differences between excitation energies are discussed and compared to the absorption spectrum of perylene in gas phase and diluted solution. De‐excitation energy from the relaxed geometry of the lowest excited singlet is in good agreement with the experimental fluorescence emission. Optimization of several coplanar forms of the perylene pair prove that, contrary to generalized gradient approximation (GGA) and hybrid exchange‐correlation functionals, corrected TDDFT is able to bind the perylene dimer in the ground state. Excitation energies from different dimer conformers point to dimer formation prior to photoexcitation. The fully relaxed excimer geometry belongs to the perfectly eclipsed conformation with D2h symmetry. The excimer equilibrium intermolecular distance is shorter than the separation found for the ground state, which is an indication of stronger interchromophore interaction in the excimer state. Excimer de‐excitation energy is in rather good agreement with the excimer band of perylene in concentrated solution. The study also scans the energy profiles of the ground and lowest excited states along several geometrical distortions. The nature of the interactions responsible for the excimer stabilization is explored in terms of excitonic and charge resonance contributions. © 2015 Wiley Periodicals, Inc.

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Section: Introductionsupporting

confidence: 57%

Theoretical investigations of the perylene electronic structure: Monomer, dimers, and excimers

Casanova

2015

Int. J. Quantum Chem.

105

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“…The orientational order parameter ξ is calculated for a simulation snapshot by averaging the local orientational orderover all pairs of neighboring molecules, where o i and o j are the unit orientation vectors for molecules i and j whose COM separation is less than R in,cut . 54 The in-plane orientation vector o for perylene is defined to be orthogonal to the bonds connecting naphthalene rings and is depicted by a black arrow in Figure 1c. In perylothiophene, the direction of orientation vector o is defined from the center-of-mass of the perylene core to the sulfur atom, as shown in Figure 1d.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Computational Sampling of Perylene and Perylothiophene Packing with Rigid-Body Models

2017

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Molecular simulations have the potential to advance the understanding of how the structure of organic materials can be engineered through the choice of chemical components but are limited by computational costs. The computational costs can be significantly lowered through the use of modeling approximations that capture the relevant features of a system, while lowering algorithmic complexity or by decreasing the degrees of freedom that must be integrated. Such methods include coarse-graining techniques, approximating long-range electrostatics with short-range potentials, and the use of rigid bodies to replace flexible bonded constraints between atoms. To understand whether and to what degree these techniques can be leveraged to enhance the understanding of planar organic molecules, we investigate the morphologies predicted by molecular dynamic simulations using simplified molecular models of perylene and perylothiophene. Approximately, 10 000 wall-clock hours of graphics processing unit-accelerated simulations are performed using both rigid and flexible models to test their efficiency and predictive capability with the two chemistries. We characterize the 1191 resulting morphologies using simulated X-ray diffraction and cluster analysis to distinguish structural transitions, summarized by four phase diagrams. We find that the morphologies generated by the rigid model of perylene and perylothiophene match with those generated by the flexible model. We find that ordered, hexagonally packed columnar phases are thermodynamically favored over a wide range of densities and temperatures for both molecules, in qualitative agreement with experiments. Furthermore, we find the rigid model to be more computationally efficient for both molecules, providing more samples per second and shorter times to equilibrium. Owing to the structural accuracy and improved computational efficiency of modeling polyaromatic groups as rigid bodies, we recommend this modeling choice for enhancing the sampling in polyaromatic molecular simulations.

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“…Former calculations using B3LYP functional finds the ground state potential energy of this dimer to be repulsive [27]. This behavior is obviously a result of the functional used and in fact using M06-2x a minimum is found at z = 3.7 Å.…”

Section: Parallel Stacked Dimermentioning

confidence: 98%

Dimer formation of perylene: An ultracold spectroscopic and computational study

Birer

Yurtsever

2015

Journal of Molecular Structure

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Theoretical Investigation of Perylene Dimers and Excimers and Their Signatures in X-Ray Diffraction

Cited by 18 publications

References 51 publications

Theoretical investigations of the perylene electronic structure: Monomer, dimers, and excimers

Theoretical investigations of the perylene electronic structure: Monomer, dimers, and excimers

Enhanced Computational Sampling of Perylene and Perylothiophene Packing with Rigid-Body Models

Dimer formation of perylene: An ultracold spectroscopic and computational study

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