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Kazuyoshi Tanaka - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamical Vibronic Coupling constant and density: Chemical potential and Vibronic Coupling in reactions
Chemical Physics Letters, 2016Co-Authors: Tohru Sato, Naoki Haruta, Kazuyoshi TanakaAbstract:Abstract Vibronic Coupling constant (VCC) and density (VCD) defined for a pure state, which have been successfully applied for reactions of fullerenes and nanographenes as reactivity indices, are extended for a mixed state. The extended VCC and VCD, thermodynamical Vibronic Coupling constant (ThVCC) and density (ThVCD), are formulated in the finite-temperature grand-canonical ensemble. ThVCD can be applied for charge transfer of a fractional number of electron. Based on the total differential of chemical potential, the relationship between chemical potential, absolute hardness, and Vibronic Coupling in a bimolecular reaction is discussed.
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reactivity index for diels alder cycloadditions to large polycyclic aromatic hydrocarbons using Vibronic Coupling density
Tetrahedron Letters, 2015Co-Authors: Naoki Haruta, Tohru Sato, Kazuyoshi TanakaAbstract:The cycloaddition reactivities of perylene (C20H12), bisanthene (C28H14), and tribenzoperylene (C30H16) are theoretically investigated with Vibronic Coupling density analysis. Their HOMOs are strongly delocalized over the molecules, and therefore the reactive sites are smeared. Vibronic Coupling density analysis clearly shows that the bay regions of armchair edges are reactive. This is consistent with experimental findings that maleic anhydride attacks the bay regions.
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Fluorescent triphenylamine derivative: Theoretical design based on reduced Vibronic Coupling
Chemical Physics Letters, 2014Co-Authors: Yuichiro Kameoka, Tohru Sato, Masashi Uebe, Akihiro Ito, Kazuyoshi TanakaAbstract:Abstract A triphenylamine derivative containing monocarborane was designed to exhibit fluorescence by considering Vibronic Couplings in the non-fluorescent parent compound. Off-diagonal Vibronic Coupling constants, which govern the rate constant of non-radiative transitions, were reduced. Based on analysis of Vibronic Coupling densities, this reduction was attributed to the fact that the highest occupied molecular orbital (HOMO), which is localized on the unsubstituted triphenylamine, became partly delocalized to monocarborane in the derivative, while the lowest unoccupied molecular orbital (LUMO) was strongly localized on triphenylamine. This suggests a design principle for the suppression of non-radiative decay in light-emitting materials.
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Reaction mechanism in the mechanochemical synthesis of dibenzophenazine: application of Vibronic Coupling density analysis
Tetrahedron Letters, 2013Co-Authors: Naoki Haruta, Tohru Sato, Kazuyoshi Tanaka, Michel BaronAbstract:The reaction mechanism for mechanochemical synthesis of dibenzophenazine was theoretically investigated in terms of the Vibronic Coupling density, which describes the interactions between electrons and nuclear motions. The concept theoretically indicates experimentally observed reactive sites that cannot be explained by the conventional frontier orbital theory. The results of Vibronic Coupling density analysis suggested the difference between reaction mechanisms under thermal and mechanochemical conditions.
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Vibronic Coupling density analysis for the chain-length dependence of reorganization energies in oligofluorenes: a comparative study with oligothiophenes
Physical chemistry chemical physics : PCCP, 2013Co-Authors: Motoyuki Uejima, Tohru Sato, Kazuyoshi Tanaka, Hironori KajiAbstract:The Vibronic Coupling constants and reorganization energies of oligofluorenes OF(n) (n = 1-6) are calculated for their cationic states (hole transport). Those of oligothiophenes OT(2n) (n = 1-6) are also calculated for comparison. The Vibronic Coupling constants of OF(n) are smaller than those of OT(2n), and decrease with increasing n. For the elucidation of the small Vibronic Couplings of the oligofluorenes, the calculated Vibronic Coupling constants are analyzed on the basis of the concept of Vibronic Coupling density. The Vibronic Coupling density of OF(n) becomes small in the middle of the chain with increasing n because of the reduction in the electron-density difference between the neutral and cationic states. It is found that orbital relaxation plays a crucial role in the distribution of the electron-density difference. From the fragment molecular orbital analyses, the large orbital relaxation in OF(n) is found to originate from the small transfer integral between the fragment molecular orbitals. These findings led to a design principle for a carrier-transporting oligomer/polymer with small Vibronic Couplings, or small reorganization energy, as follows: the orbital interaction between the monomers should be small from the view of Vibronic Couplings.
Tohru Sato - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamical Vibronic Coupling constant and density: Chemical potential and Vibronic Coupling in reactions
Chemical Physics Letters, 2016Co-Authors: Tohru Sato, Naoki Haruta, Kazuyoshi TanakaAbstract:Abstract Vibronic Coupling constant (VCC) and density (VCD) defined for a pure state, which have been successfully applied for reactions of fullerenes and nanographenes as reactivity indices, are extended for a mixed state. The extended VCC and VCD, thermodynamical Vibronic Coupling constant (ThVCC) and density (ThVCD), are formulated in the finite-temperature grand-canonical ensemble. ThVCD can be applied for charge transfer of a fractional number of electron. Based on the total differential of chemical potential, the relationship between chemical potential, absolute hardness, and Vibronic Coupling in a bimolecular reaction is discussed.
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reactivity index for diels alder cycloadditions to large polycyclic aromatic hydrocarbons using Vibronic Coupling density
Tetrahedron Letters, 2015Co-Authors: Naoki Haruta, Tohru Sato, Kazuyoshi TanakaAbstract:The cycloaddition reactivities of perylene (C20H12), bisanthene (C28H14), and tribenzoperylene (C30H16) are theoretically investigated with Vibronic Coupling density analysis. Their HOMOs are strongly delocalized over the molecules, and therefore the reactive sites are smeared. Vibronic Coupling density analysis clearly shows that the bay regions of armchair edges are reactive. This is consistent with experimental findings that maleic anhydride attacks the bay regions.
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Fluorescent triphenylamine derivative: Theoretical design based on reduced Vibronic Coupling
Chemical Physics Letters, 2014Co-Authors: Yuichiro Kameoka, Tohru Sato, Masashi Uebe, Akihiro Ito, Kazuyoshi TanakaAbstract:Abstract A triphenylamine derivative containing monocarborane was designed to exhibit fluorescence by considering Vibronic Couplings in the non-fluorescent parent compound. Off-diagonal Vibronic Coupling constants, which govern the rate constant of non-radiative transitions, were reduced. Based on analysis of Vibronic Coupling densities, this reduction was attributed to the fact that the highest occupied molecular orbital (HOMO), which is localized on the unsubstituted triphenylamine, became partly delocalized to monocarborane in the derivative, while the lowest unoccupied molecular orbital (LUMO) was strongly localized on triphenylamine. This suggests a design principle for the suppression of non-radiative decay in light-emitting materials.
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Reaction mechanism in the mechanochemical synthesis of dibenzophenazine: application of Vibronic Coupling density analysis
Tetrahedron Letters, 2013Co-Authors: Naoki Haruta, Tohru Sato, Kazuyoshi Tanaka, Michel BaronAbstract:The reaction mechanism for mechanochemical synthesis of dibenzophenazine was theoretically investigated in terms of the Vibronic Coupling density, which describes the interactions between electrons and nuclear motions. The concept theoretically indicates experimentally observed reactive sites that cannot be explained by the conventional frontier orbital theory. The results of Vibronic Coupling density analysis suggested the difference between reaction mechanisms under thermal and mechanochemical conditions.
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Vibronic Coupling density analysis for the chain-length dependence of reorganization energies in oligofluorenes: a comparative study with oligothiophenes
Physical chemistry chemical physics : PCCP, 2013Co-Authors: Motoyuki Uejima, Tohru Sato, Kazuyoshi Tanaka, Hironori KajiAbstract:The Vibronic Coupling constants and reorganization energies of oligofluorenes OF(n) (n = 1-6) are calculated for their cationic states (hole transport). Those of oligothiophenes OT(2n) (n = 1-6) are also calculated for comparison. The Vibronic Coupling constants of OF(n) are smaller than those of OT(2n), and decrease with increasing n. For the elucidation of the small Vibronic Couplings of the oligofluorenes, the calculated Vibronic Coupling constants are analyzed on the basis of the concept of Vibronic Coupling density. The Vibronic Coupling density of OF(n) becomes small in the middle of the chain with increasing n because of the reduction in the electron-density difference between the neutral and cationic states. It is found that orbital relaxation plays a crucial role in the distribution of the electron-density difference. From the fragment molecular orbital analyses, the large orbital relaxation in OF(n) is found to originate from the small transfer integral between the fragment molecular orbitals. These findings led to a design principle for a carrier-transporting oligomer/polymer with small Vibronic Couplings, or small reorganization energy, as follows: the orbital interaction between the monomers should be small from the view of Vibronic Couplings.
Hironori Kaji - One of the best experts on this subject based on the ideXlab platform.
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Vibronic Coupling density analysis for the chain-length dependence of reorganization energies in oligofluorenes: a comparative study with oligothiophenes
Physical chemistry chemical physics : PCCP, 2013Co-Authors: Motoyuki Uejima, Tohru Sato, Kazuyoshi Tanaka, Hironori KajiAbstract:The Vibronic Coupling constants and reorganization energies of oligofluorenes OF(n) (n = 1-6) are calculated for their cationic states (hole transport). Those of oligothiophenes OT(2n) (n = 1-6) are also calculated for comparison. The Vibronic Coupling constants of OF(n) are smaller than those of OT(2n), and decrease with increasing n. For the elucidation of the small Vibronic Couplings of the oligofluorenes, the calculated Vibronic Coupling constants are analyzed on the basis of the concept of Vibronic Coupling density. The Vibronic Coupling density of OF(n) becomes small in the middle of the chain with increasing n because of the reduction in the electron-density difference between the neutral and cationic states. It is found that orbital relaxation plays a crucial role in the distribution of the electron-density difference. From the fragment molecular orbital analyses, the large orbital relaxation in OF(n) is found to originate from the small transfer integral between the fragment molecular orbitals. These findings led to a design principle for a carrier-transporting oligomer/polymer with small Vibronic Couplings, or small reorganization energy, as follows: the orbital interaction between the monomers should be small from the view of Vibronic Couplings.
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Vibronic Coupling density analysis of hole-transporting materials: Electron-density difference in DFT and HF methods
Organic Electronics, 2010Co-Authors: Katsuyuki Shizu, Tohru Sato, Kazuyoshi Tanaka, Hironori KajiAbstract:Abstract Density functional studies of Vibronic Coupling in a hole-transporting material in organic light-emitting diodes (OLED), carbazole, biphenyl and fluorene are reported as well as Hartree–Fock calculations. Vibronic Coupling density (VCD) analysis reveals that strong localization of electron-density differences on the carbazole N atom is responsible for the small Vibronic Coupling constants (VCC) of carbazole. A heteroatom bridge such as an imino group is expected to enhance hole-transporting properties, and localized electron-density difference on the atom is expected to decrease Vibronic Coupling. The difference between the density functional and Hartree–Fock calculations are discussed.
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electron vibration interactions in carrier transport material Vibronic Coupling density analysis in tpd
Chemical Physics Letters, 2008Co-Authors: Tohru Sato, Katsuyuki Shizu, Kazuyoshi Tanaka, Takako Kuga, Hironori KajiAbstract:Vibronic Coupling, or electron–vibration Coupling constant in N,N′-diphenyl-N,N′-di(m-tolyl)benzidine (TPD) cation is calculated from Vibronic Coupling integrals. The calculated constants are very small compared with other π conjugated systems. The calculated constants are analyzed on the basis of Vibronic Coupling density (VCD). The VCD analysis clearly reveals that large contributions originate from the phenyl group and tolyl group. In addition, the hole transport property of electrode-TPD molecule–electrode system is investigated using non-equilibrium Green’s function (NEGF) theory. Reflecting the small Coupling, the current suppression and power loss are less than 1/2 compared with other π conjugated systems such as oligothiophenes.
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Electron–vibration interactions in carrier-transport material: Vibronic Coupling density analysis in TPD
Chemical Physics Letters, 2008Co-Authors: Tohru Sato, Katsuyuki Shizu, Kazuyoshi Tanaka, Takako Kuga, Hironori KajiAbstract:Vibronic Coupling, or electron–vibration Coupling constant in N,N′-diphenyl-N,N′-di(m-tolyl)benzidine (TPD) cation is calculated from Vibronic Coupling integrals. The calculated constants are very small compared with other π conjugated systems. The calculated constants are analyzed on the basis of Vibronic Coupling density (VCD). The VCD analysis clearly reveals that large contributions originate from the phenyl group and tolyl group. In addition, the hole transport property of electrode-TPD molecule–electrode system is investigated using non-equilibrium Green’s function (NEGF) theory. Reflecting the small Coupling, the current suppression and power loss are less than 1/2 compared with other π conjugated systems such as oligothiophenes.
Katsuyuki Shizu - One of the best experts on this subject based on the ideXlab platform.
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Vibronic Coupling density and related concepts
Journal of Physics: Conference Series, 2013Co-Authors: Tohru Sato, Naoya Iwahara, Katsuyuki Shizu, Motoyuki Uejima, Naoki Haruta, Kazuyoshi TanakaAbstract:Vibronic Coupling density is derived from a general point of view as a one-electron property density. Related concepts as well as their applications are presented. Linear and nonlinear Vibronic Coupling density and related concepts, orbital Vibronic Coupling density, reduced Vibronic Coupling density, atomic Vibronic Coupling constant, and effective Vibronic Coupling density, illustrate the origin of Vibronic Couplings and enable us to design novel functional molecules or to elucidate chemical reactions. Transition dipole moment density is defined as an example of the one-electron property density. Vibronic Coupling density and transition dipole moment density open a way to design light-emitting molecules with high efficiency.
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Vibronic Coupling density analysis for free-base porphin cation
Chemical Physics Letters, 2011Co-Authors: Katsuyuki Shizu, Tohru Sato, Kazuyoshi TanakaAbstract:Abstract We calculate Vibronic Coupling constants (VCCs) and reduced Vibronic Coupling densities (RVCDs) of free-base porphin (FBP) cation whose derivatives are employed as hole-transporting molecules in organic field-effect transistors (OFETs). The FBP cation has small VCCs as a π-conjugated molecule. Vibronic Coupling density (VCD) analysis reveals that strong localization of the electron-density difference on the meso-carbon atoms between the cationic and neutral states leads to the small VCCs of the FBP cation. This study is a starting point for understanding Vibronic Couplings in a hole-transport process through porphyrin thin films.
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Reduced Vibronic Coupling density and its application to bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF)
Chemical Physics Letters, 2010Co-Authors: Katsuyuki Shizu, Tohru Sato, Kazuyoshi TanakaAbstract:Abstract Reduced Vibronic Coupling density (RVCD) and reduced atomic Vibronic Coupling density (RAVCD) are introduced in order to discuss the origin of Vibronic (electron–vibration) Couplings in a molecule. As an example, the RVCDs and RAVCDs of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) cation are presented. The strongest Vibronic Coupling of the C C stretching mode originates from large electron-density difference on the C C bond.
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Vibronic Coupling density analysis of hole-transporting materials: Electron-density difference in DFT and HF methods
Organic Electronics, 2010Co-Authors: Katsuyuki Shizu, Tohru Sato, Kazuyoshi Tanaka, Hironori KajiAbstract:Abstract Density functional studies of Vibronic Coupling in a hole-transporting material in organic light-emitting diodes (OLED), carbazole, biphenyl and fluorene are reported as well as Hartree–Fock calculations. Vibronic Coupling density (VCD) analysis reveals that strong localization of electron-density differences on the carbazole N atom is responsible for the small Vibronic Coupling constants (VCC) of carbazole. A heteroatom bridge such as an imino group is expected to enhance hole-transporting properties, and localized electron-density difference on the atom is expected to decrease Vibronic Coupling. The difference between the density functional and Hartree–Fock calculations are discussed.
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Vibronic Coupling Constant and Vibronic Coupling Density
Springer Series in Chemical Physics, 2009Co-Authors: Tohru Sato, K. Tokunaga, Naoya Iwahara, Katsuyuki Shizu, Kazuyoshi TanakaAbstract:The Jahn–Teller effect [7–9, 25] originates from Vibronic Coupling [19]. In this chapter, we discuss the definition of Vibronic Coupling with emphasis on its difference from non-adiabatic Coupling. We present one of the methods for calculation of the Vibronic Coupling constant and Vibronic Coupling density analysis that enables us to investigate the local properties of Vibronic Coupling. Some applications of Vibronic Coupling density are presented. Vibronic Couplings in fullerene ions still contain some unresolved problems as targets for the calculations. Studies on Vibronic Couplings in fullerene ions are reviewed.
Hans-dieter Meyer - One of the best experts on this subject based on the ideXlab platform.
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A generalised Vibronic-Coupling Hamiltonian model for benzopyran
The Journal of chemical physics, 2014Co-Authors: Loïc Joubert-doriol, Benjamin Lasorne, David Lauvergnat, Hans-dieter Meyer, Fabien GattiAbstract:A new general model for describing intersecting multidimensional potential energy surfaces when motions of large amplitude are involved is presented. This model can be seen as an extension of the Vibronic Coupling models of Koppel et al. [“Multimode molecular dynamics beyond the Born-Oppenheimer approximation,” Adv. Chem. Phys. 57, 59 (1984)]. In contrast to the original Vibronic Coupling models, here the number of diabatic states is larger than the number of adiabatic states and curvilinear coordinates are used in a systematic way. Following general considerations, the approach is applied to the fitting of the potential energy surfaces for the very complex nonadiabatic photodynamics of benzopyran. Preliminary results are presented at the complete active space self-consistent field level of theory and with up to 12 active degrees of freedom. Special emphasis is placed on the physical interpretation of the diabatic states and on the influence of the various degrees of freedom on the fit.
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Vibronic Coupling Effects in Resonant Auger Spectra of H 2 O
Journal of Physical Chemistry A, 2012Co-Authors: Matthis Eroms, Martin Jungen, Hans-dieter MeyerAbstract:We present a theoretical investigation of the resonant Auger effect in gas-phase water. As in our earlier work, the simulation of nuclear dynamics is treated in a one-step picture, because excitation and decay events cannot be disentangled. Extending this framework, we now account for the Vibronic Coupling in the cationic final states arising from degeneracies in their potential energy surfaces (PESs). A diabatization of the cationic states permits a correct treatment of non Born-Oppenheimer dynamics leading to a significantly better agreement with experimental results. Moreover, we arrive at a more balanced understanding of the various spectral features that can be attributed to nuclear motion in the core-excited state or to Vibronic Coupling effects. The nuclear equations of motion have been solved using the multiconfiguration time-dependent Hartree (MCTDH) method. The cationic PESs were recalculated using the coupled electron pair approach (CEPA) whereas previously a multireference configuration interaction method had been employed.
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Vibronic Coupling effects in resonant auger spectra of H2O.
The journal of physical chemistry. A, 2012Co-Authors: Matthis Eroms, Martin Jungen, Hans-dieter MeyerAbstract:We present a theoretical investigation of the resonant Auger effect in gas-phase water. As in our earlier work, the simulation of nuclear dynamics is treated in a one-step picture, because excitation and decay events cannot be disentangled. Extending this framework, we now account for the Vibronic Coupling in the cationic final states arising from degeneracies in their potential energy surfaces (PESs). A diabatization of the cationic states permits a correct treatment of non Born-Oppenheimer dynamics leading to a significantly better agreement with experimental results. Moreover, we arrive at a more balanced understanding of the various spectral features that can be attributed to nuclear motion in the core-excited state or to Vibronic Coupling effects. The nuclear equations of motion have been solved using the multiconfiguration time-dependent Hartree (MCTDH) method. The cationic PESs were recalculated using the coupled electron pair approach (CEPA) whereas previously a multireference configuration interaction method had been employed.
