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118 results on '"Schweitzer, Gerd"'

7. Solvent effects on hole-edge structure for single-wall carbon nanotubes and single-wall carbon nanohorns

Author

Miyawaki, Jin, Yudasaka, Masako, Iijima, Sumio, Fron, Eduard, Jordens Sven, Schweitzer, Gerd, Weil, Tanja, Mullen, Klaus, Verhoeven, Jan W., Auweraer, Mark Van der, and Schryver, Frans C. De

Subjects
Solvents -- Observations, Nanotubes -- Usage, Carbon -- Research, Carbon -- Chemical properties, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

Two kinds of carbon nanotubes (CNTs) are selected to investigate hole-edge reactivity such as single-wall carbon nanotubes (SWNTs) and single-wall carbon nanohorns (SWNHs). The study is helpful to the understanding of hole-edge chemistry and would enable the production of well-designed carbonaceous materials with high functionality.

Published
2004

8. Photophysical study of electron-transfer and energy-hopping processes in first-generation mono- and multichromophoric triphenylamine core dendrimers

Author

Lor, Marc, Viaene, Lucien, Pilot, Roberto, Fron, Eduard, Jordens Sven, Schweitzer, Gerd, Weil, Tanja, Mullen, Klaus, Verhoeven, Jan W., Auweraer, Mark Van der, and Schryver, Frans C. De

Subjects
Dendrimers -- Research, Dendrimers -- Atomic properties, Electron transport -- Observations, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

The electron-transfer process in mono- (NlP1) and multichromophoric (NlP3) triphenylamine core dendrimers carrying one and three peryleneimide electron accepter chromophores, are characterized using the combination of transient absorption and fluorescence experiments performed on a femtosecond to nanosecond time scale.

Published
2004

9. Intramolecular directional energy transfer processes in dendrimers containing perylene and terrylene chromophores

Author

Schweitzer, Gerd, Gronheid, Roel, Jordens, Sven, Lor, Marc, Bleder, Gino De, Weil, Tanja, Reuther, Erik, Mullen, Klaus, and De Schryver, Frans C.

Subjects
Energy transfer -- Analysis, Chromophores -- Research, Dendrimers -- Thermal properties, Dendrimers -- Research, Chemicals, plastics and rubber industries
Abstract

The time-resolved fluorescence kinetics of a first and a second generation dendrimer with peryleneimide chromophores at the rim and a terrylenediimide chromophore in the core were investigated. Analysis of the in-the-bay area substituted terrylenediimide model compound reveals subsets of molecules showing different relaxation pathways of the terrylene core.

Published
2003

10. Picosecond dynamics of excited 9,9'-bianthryl adsorbed on porous glass: role of symmetry breaking in the ground state

Author

Tsuboi, Yasuyuki, Kumagai, Tamami, Shimizu, Masato, Itaya, Akira, Schweitzer, Gerd, Schryver, Frans C. de, Asahi, Tsuyoshi, Masuhara, Horishi, and Miyasaka, Hiroshi

Subjects
Chemistry, Physical and theoretical -- Research, Dynamics -- Analysis, Porous materials -- Physiological aspects, Adsorption -- Analysis, Fluorescence -- Physiological aspects, Chemicals, plastics and rubber industries
Published
2002

11. The influence of meso-substitution on the photophysical behavior of some thiacarbocyanine dyes in dilute solution

Author

Vranken, Nadia, Jordens, Sven, De Belder, Gino, Lor, Marc, Rousseau, Els, Schweitzer, Gerd, Toppet, Suzanne, Auweraer, Mark van der, and De Schryver, Frans C.

Subjects
Chemistry, Physical and theoretical -- Research, Carbon -- Physiological aspects, Cyanides -- Physiological aspects, Dyes and dyeing -- Chemistry, Solution (Chemistry) -- Physiological aspects, Photochemical research -- Analysis, Chemicals, plastics and rubber industries
Published
2001

12. Correlation between ground state conformation and excited state dynamics in a multichromophoric dendrimer studied by excitation wavelength dependent fluorescence upconversion

Author

Karni, Yoram, Jordens, Sven, De Belder, Gino, Hofkens, Johan, Schweitzer, Gerd, De Schryver, Frans C., Herrman, Andreas, and Mullen, Klaus

Subjects
Chemistry, Physical and theoretical -- Research, Macromolecules -- Research, X-ray spectroscopy -- Usage, Chemicals, plastics and rubber industries
Abstract

A new study uses time-resolved fluorescence excitation spectroscopy to investigate the correlation between ground state conformation and excited state dynamics in a multichromophoric dendrimer.

Published
1999

14. Fluorescence spectroscopy of the longwave chlorophylls in trimeric and monomeric photosystem I core complexes from the cyanobacterium spirulina platensis

Author

Karapetyan, Navassard V., Dorra, Dieter, Schweitzer, Gerd, Bezsmertnaya, Irina N., and Holzwarth, Alfred R.

Subjects
Chlorophyll -- Observations, Spirulina -- Research, Fluorescence spectroscopy -- Usage, Biological sciences, Chemistry
Abstract

A study of the role of longwave chlorophylls (Chl) in the energy migration in photosystem I (PSI) antenna of cyanobacteria was undertaken. The PSI trimeric and monomeric complexes were isolated from Spirulina, and stationary fluorescence emission and excitation spectra of PSI trimers and monomers were studied. The results showed that at least some of the longwave Chls occur at physiological conditions.

Published
1997

16. Ultrafast excited-state dynamics of the photoswitchable protein Dronpa

Author

Fron, Eduard, Schweitzer, Gerd, Flors, Cristina, Habuchi, Satoshi, Mizuno, Hideaki, Ando, Ryoko, De Schryver, Frans C., Miyawaki, Atsushi, and Hofkens, Johan

Subjects
Absorption spectra -- Analysis, Bacterial proteins -- Structure, Bacterial proteins -- Optical properties, Bacterial proteins -- Spectra, Excited state chemistry -- Research, Chemistry
Abstract

An ultrafast transient absorption spectroscopy analysis of Dronpa is done to determine the rate for the initial step of photoswitching from the neutral dark form to the intermediate which emerges to the anionic fluorescent form. It is shown that the acid-induced protonated form and the photoconverted protonated form are two different spectroscopic types.

Published
2007

17. CT-CT annihilation in rigid perylene end-capped pentaphenylenes

Author

Fron, Eduard, Bell, Toby D.M., Vooren, Antoine Van, Schweitzer, Gerd, Cornil, John, Auweraer, Mark Van der, and De Schryer, Frans C.

Subjects
Quantum chemistry -- Research, Charge transfer -- Research, Chemistry
Abstract

The time-dependent spectral properties of a rigid, extended system consisting of three pentaphenylene units end-capped with perylene monoimide are studied by femtosecond transient absorption and single photon timing measurements. It is seen that quantum-chemical calculations performed on the system comprising of two pentaphenylene units end-capped with perylene monoimide support the experimental data.

Published
2007

19. Singlet - Singlet Annihilation in Multichromophoric Peryleneimide Dendrimers, Determined by Fluorescence Upconversion

Author

Belder, Gino De, Schweitzer, Gerd, Jordens, Sven, Lor, Marc, Mitra, Sivaprasad, Hofkens, Johan, Feyter, Steven De, Auweraer, Mark Van der, Herrmann, Andreas, Weil, Tanja, Müllen, Klaus, Schryver, Frans C. De, Zernike Institute for Advanced Materials, Polymer Chemistry and Bioengineering, and Nanotechnology and Biophysics in Medicine (NANOBIOMED)

Subjects
kinetics, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, fluorescence spectroscopy, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), time-resolved spectroscopy, dendrimers
Published
2001

21. Energy and Electron Transfer in Ethynylene Bridged Perylene Diimide Multichromophores

Author

Flors, Cristina, Oesterling, Ingo, Schnitzler, Tobias, Fron, Eduard, Schweitzer, Gerd, Sliwa, Michel, Herrmann, Andreas, Auweraer, Mark van der, Schryver, Frans C. de, Müllen, Klaus, Hofkens, Johan, Flors, Cristina, Oesterling, Ingo, Schnitzler, Tobias, Fron, Eduard, Schweitzer, Gerd, Sliwa, Michel, Herrmann, Andreas, Auweraer, Mark van der, Schryver, Frans C. de, Müllen, Klaus, and Hofkens, Johan

Abstract

Shape persistent perylene diimide (PDI) multichromophores incorporating ethynylene bridges have been synthesized in high yield via palladium-catalyzed Hagihara coupling, which provides compounds with no rotational or constitutional isomerism in contrast to polyphenylene dendrimers. Their excited-state pathways have been studied at the ensemble and at the single-molecule level and compared to several model compounds. In an apolar solvent, energy hopping and/or energy transfer between the chromophoric units are the dominating processes. In a polar medium, energy hopping is still operative, but electron transfer from the phenyl ethynylene bridge to the chromophore occurs if the former is connected to the bay area of PDI. This effect should be considered when further developing this type of multichromophore, as this nonradiative deactivation process might be unwanted for applications such as optical and electronic devices. At the single-molecule level, the fluorescence intensity traces are characterized by rich on-off dynamics, which we attribute to oxygen-enhanced intersystem crossing leading to the formation of a long-lived dark charge-separated state.

Published
2007

23. Energy- and Angle-Resolved Femtosecond Photoelectron Spectra from Rotating Molecules

Author

De Schryver, Frans C., De Feyter, Steven, Schweitzer, Gerd, Arasaki, Yasuki, Takatsuka, Kazuo, Wang, Kwanghsi, McKoy, Vincent, De Schryver, Frans C., De Feyter, Steven, Schweitzer, Gerd, Arasaki, Yasuki, Takatsuka, Kazuo, Wang, Kwanghsi, and McKoy, Vincent

Abstract

We have extended our formulation of energy- and angle-dependent pump-probe photoelectron spectroscopy for vibrational wavepackets to account for the effects of molecular rotation. We employ a classical model for rotation, which should be applicable to many cases of interest, and present some results of applications to photoelectron spectra for wavepackets on the double-minimum state of Na_2. The results provide useful insights into such time-resolved photoelectron spectra and suggest strategies for deconvolution of the vibrational and rotational content of the photoelectron signals.

Published
2001

26. CT−CT Annihilation in Rigid Perylene End-Capped Pentaphenylenes

Author

Fron, Eduard, primary, Bell, Toby D. M., additional, Van Vooren, Antoine, additional, Schweitzer, Gerd, additional, Cornil, Jérôme, additional, Beljonne, David, additional, Toele, Paul, additional, Jacob, Josemon, additional, Müllen, Klaus, additional, Hofkens, Johan, additional, Van der Auweraer, Mark, additional, and De Schryver, Frans C., additional

Published
2006
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31. Singlet-Singlet Annihilation in Multichromophoric Peryleneimide Dendrimers, Determined by Fluorescence Upconversion

Author

De Belder, Gino, primary, Schweitzer, Gerd, additional, Jordens, Sven, additional, Lor, Marc, additional, Mitra, Sivaprasad, additional, Hofkens, Johan, additional, De Feyter, Steven, additional, Van der Auweraer, Mark, additional, Herrmann, Andreas, additional, Weil, Tanja, additional, Müllen, Klaus, additional, and De Schryver, Frans C., additional

Published
2001
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