Hubert Staerk - Academia.edu (original) (raw)

Papers by Hubert Staerk

Research paper thumbnail of Design considerations and performance of a spectro-streak apparatus applying a planar LIGA microspectrometer for time-resolved ultrafast fluorescence spectroscopy

Review of Scientific Instruments, Jul 1, 1996

Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer wit... more Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer with a self-focusing reflection grating are reported. The microspectrometer chip (dimensions: 17×6.4 mm2; 125 mum effective thickness of the three-layer x-ray resist system), fabricated with the versatile LIGA technique, has been adapted to a picosecond streak camera. Performance tests have been carried out with a fluorescent probe exhibiting a dynamic Stokes shift of the exciplex fluorescence band due to solvation of the charge transfer dipole within about 400 ps. The use of a LIGA microspectrometer in ultrafast spectroscopy proved to be of advantage in time-resolved studies of complex luminescence spectra where a moderate spectral resolution is required and a large spectral range must be covered.

Research paper thumbnail of Magnetic Field Effect in the Recombination Reaction of Radical Ion Pairs: Dependence on Solvent Dielectric Constant

The Journal of Physical Chemistry, 1995

Research paper thumbnail of Estimation of the probability distribution of end-group distances of chain-linked electron donor-acceptor molecules and radical ion pairs: a Monte-Carlo approach

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Temperature study of the magnetic field effect in photogenerated flexibly-linked radical ion pairs: influence of the stochastically modulated exchange interaction

The Journal of Physical Chemistry, 1991

Research paper thumbnail of Design considerations and performance of a spectro-streak apparatus applying a planar LIGA microspectrometer for time-resolved ultrafast fluorescence spectroscopy

Review of Scientific Instruments, Jul 1, 1996

Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer wit... more Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer with a self-focusing reflection grating are reported. The microspectrometer chip (dimensions: 17×6.4 mm2; 125 μm effective thickness of the three-layer x-ray resist system), fabricated with the versatile LIGA technique, has been adapted to a picosecond streak camera. Performance tests have been carried out with a fluorescent probe exhibiting a dynamic Stokes shift of the exciplex fluorescence band due to solvation of the charge transfer dipole within about 400 ps. The use of a LIGA microspectrometer in ultrafast spectroscopy proved to be of advantage in time-resolved studies of complex luminescence spectra where a moderate spectral resolution is required and a large spectral range must be covered.

Research paper thumbnail of Electron Transfer, Solvation, and Amplified Stimulated Emission of Pyrene-DMA and Anthracene-DMA

The Journal of Physical Chemistry, 1995

ABSTRACT

Research paper thumbnail of Magnetic field dependent reaction yields from radical ion pairs linked by a partially rigid aliphatic chain

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Intramolecular Charge Transfer (ICT) and Solvation of a Rigidly Linked Pyrene/ N -Methylindolino Derivative and Related Compounds in Linear Alcohols

The Journal of Physical Chemistry a, 1997

ABSTRACT Measurements on a rather rigid and coplanar bichromophoric compound have been carried ou... more ABSTRACT Measurements on a rather rigid and coplanar bichromophoric compound have been carried out with respect to intramolecular charge separation, as well as regarding solvation and lifetime of the CT state in alcohol solutions. The results indicate that the CT step proceeds very efficiently followed by a Stokes shift of the CT emission band governed by the dielectric relaxation of the solvent (a series of n-alcohols). The average Stokes-shift time, τsolv (of a few hundred picoseconds), correlates directly with the longitudinal relaxation time, τL = (ε∞/εs)τD, of the solvent. The recently developed single-shot spectrostreak picosecond technique was used for the collection of the time-resolved emission spectra.

Research paper thumbnail of Electronic interaction and charge transfer efficiencies in triaromatic donor–acceptor systems. An experimental and theoretical study

Chemical Physics Letters, Jan 2, 1998

To address the issue of electronic interaction between donor (D) and acceptor (A) moieties in int... more To address the issue of electronic interaction between donor (D) and acceptor (A) moieties in intramolecular charge transfer reactions a series of chemically closely related extended pi-systems has been investigated. These compounds contain pyrene and organic methyl ester derivatives connected via a phenyl group. Our steady-state fluorescence studies reveal that only particular compounds exhibit strong charge transfer (CT) emission in solution. To elucidate the experimental results we have performed semiempirical CNDO/S-CI calculations which indicate that the electronic coupling and Coulomb stabilization of the CT state are strongly dependent on the nodal properties of the D/A orbitals.

Research paper thumbnail of Magnetic-field effects on geminate radical-pair recombination

Faraday Discussions of the Chemical Society, 1984

Research paper thumbnail of Magnetic field dependent reaction yields from radical ion pairs linked by a partially rigid aliphatic chain

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Time-Resolved Fluorescence and Solvatochromy of Directly Linked Pyrene−DMA Derivatives in Alcoholic Solution

The Journal of Physical Chemistry B, 2001

... Simone Techert,* † Alexander Wiessner, † Stefan Schmatz, ‡ and Hubert Staerk* †. Max-Planck-I... more ... Simone Techert,* † Alexander Wiessner, † Stefan Schmatz, ‡ and Hubert Staerk* †. Max-Planck-Institut für biophysikalische Chemie, Abteilung Spektroskopie und Photochemische Kinetik, Am Fassberg 11, D-37077 Göttingen ...

Research paper thumbnail of Delayed luminescence of naphthalene in isooctane spectral, lifetime, and magnetic field studies of delayed fluorescence and monomer phosphorescence at 293 K

The Journal of Physical Chemistry, 1991

ABSTRACT

Research paper thumbnail of Intramolecular Electron Hopping in Double Carbazole Molecules Studied by the Fluorescence-Detected Magnetic Field Effect

The Journal of Physical Chemistry a, 1999

ABSTRACT

Research paper thumbnail of Metal-Ion Detection by the Magnetic-Field-Sensitive Fluorescence of Intramolecular Exciplexes Containing Aza-Crown-Ether Moieties as Electron Donor

The Journal of Physical Chemistry A, 1997

Research paper thumbnail of Photophysical Characteristics of Directly Linked Pyrene−Dimethylaniline Derivatives

The Journal of Physical Chemistry A, 2000

ABSTRACT Experimental and theoretical investigations of the spectroscopic properties have been ca... more ABSTRACT Experimental and theoretical investigations of the spectroscopic properties have been carried out on three charge-transfer model systems, covalently linked donor−acceptor compounds of the type pyrene and derivatives of N,N−dimethylaniline (dimethyl(4-pyren-1-ylphenyl)amine (PyDMA), dimethyl(3-methyl-4-pyren-1-ylphenyl)amine (PyMDMA), and (3,5-dimethyl-4-pyren-1-ylphenyl)dimethylamine (PyDMDMA)). Comparing stationary absorption and emission spectra as well as fluorescence lifetimes in different solvents, one can show that small chemical changes such as substitution of ortho-hydrogens by methyl groups on the DMA moiety introduces dramatic effects in spectroscopic and kinetic behavior. On the basis of infrared measurements and quantum chemical calculations, the experiments are interpreted within a statistical framework, with particular emphasis on the discussion of preferred large amplitude motion (twist angle) and pyrene-specific vibronic coupling.

Research paper thumbnail of An Energetic Model for Rapid Mixing

Review of Scientific Instruments, 1969

Research paper thumbnail of E-type delayed fluorescence depolarization, a technique to probe rotational motion in the microsecond range

Journal of Biochemical and Biophysical Methods, 1979

E (eosin)-type delayed fluorescence depolarization studies extend the time range for the measurem... more E (eosin)-type delayed fluorescence depolarization studies extend the time range for the measurement of rotational diffusion to microseconds and ms, thereby allowing investigation of slow rotational movement of macromolecules like membrane proteins. An apparatus is described for the determination of time-dependent anisotropy in this interesting time range. The method has been tested on eosin-labelled cytochrome P-450 incorporated into phospholipid membrane vesicles.

Research paper thumbnail of Photoinduced ion and ketyl radical formation in covalently linked benzophenone—dimethylaniline studied by time-resolved transient absorption spectroscopy with picosecond resolution

Journal of Photochemistry and Photobiology A: Chemistry, 1993

Research paper thumbnail of Electron transfer and magnetic field effects in covalently linked pyrenyl-oligopeptide-dimethylaniline compounds

Journal of Photochemistry and Photobiology A: Chemistry, 1995

The influence of external magnetic fields on the spin dynamics and recombination reaction yield o... more The influence of external magnetic fields on the spin dynamics and recombination reaction yield of radical ion pairs, generated by photoinduced electron transfer between pyrenyl and dimethylaniline linked by an oligopeptide bridge, was studied. From the size and characteristics of the magnetic field effect (MFE), it can be concluded that hydrogen bonds within short peptide chains (here three glycine groups) or with a hydrogen-accepting solvent (acetone) do not seem to affect significantly the chain dynamics.

Research paper thumbnail of Design considerations and performance of a spectro-streak apparatus applying a planar LIGA microspectrometer for time-resolved ultrafast fluorescence spectroscopy

Review of Scientific Instruments, Jul 1, 1996

Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer wit... more Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer with a self-focusing reflection grating are reported. The microspectrometer chip (dimensions: 17×6.4 mm2; 125 mum effective thickness of the three-layer x-ray resist system), fabricated with the versatile LIGA technique, has been adapted to a picosecond streak camera. Performance tests have been carried out with a fluorescent probe exhibiting a dynamic Stokes shift of the exciplex fluorescence band due to solvation of the charge transfer dipole within about 400 ps. The use of a LIGA microspectrometer in ultrafast spectroscopy proved to be of advantage in time-resolved studies of complex luminescence spectra where a moderate spectral resolution is required and a large spectral range must be covered.

Research paper thumbnail of Magnetic Field Effect in the Recombination Reaction of Radical Ion Pairs: Dependence on Solvent Dielectric Constant

The Journal of Physical Chemistry, 1995

Research paper thumbnail of Estimation of the probability distribution of end-group distances of chain-linked electron donor-acceptor molecules and radical ion pairs: a Monte-Carlo approach

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Temperature study of the magnetic field effect in photogenerated flexibly-linked radical ion pairs: influence of the stochastically modulated exchange interaction

The Journal of Physical Chemistry, 1991

Research paper thumbnail of Design considerations and performance of a spectro-streak apparatus applying a planar LIGA microspectrometer for time-resolved ultrafast fluorescence spectroscopy

Review of Scientific Instruments, Jul 1, 1996

Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer wit... more Results of a pilot study with a spectro-streak apparatus applying a grating microspectrometer with a self-focusing reflection grating are reported. The microspectrometer chip (dimensions: 17×6.4 mm2; 125 μm effective thickness of the three-layer x-ray resist system), fabricated with the versatile LIGA technique, has been adapted to a picosecond streak camera. Performance tests have been carried out with a fluorescent probe exhibiting a dynamic Stokes shift of the exciplex fluorescence band due to solvation of the charge transfer dipole within about 400 ps. The use of a LIGA microspectrometer in ultrafast spectroscopy proved to be of advantage in time-resolved studies of complex luminescence spectra where a moderate spectral resolution is required and a large spectral range must be covered.

Research paper thumbnail of Electron Transfer, Solvation, and Amplified Stimulated Emission of Pyrene-DMA and Anthracene-DMA

The Journal of Physical Chemistry, 1995

ABSTRACT

Research paper thumbnail of Magnetic field dependent reaction yields from radical ion pairs linked by a partially rigid aliphatic chain

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Intramolecular Charge Transfer (ICT) and Solvation of a Rigidly Linked Pyrene/ N -Methylindolino Derivative and Related Compounds in Linear Alcohols

The Journal of Physical Chemistry a, 1997

ABSTRACT Measurements on a rather rigid and coplanar bichromophoric compound have been carried ou... more ABSTRACT Measurements on a rather rigid and coplanar bichromophoric compound have been carried out with respect to intramolecular charge separation, as well as regarding solvation and lifetime of the CT state in alcohol solutions. The results indicate that the CT step proceeds very efficiently followed by a Stokes shift of the CT emission band governed by the dielectric relaxation of the solvent (a series of n-alcohols). The average Stokes-shift time, τsolv (of a few hundred picoseconds), correlates directly with the longitudinal relaxation time, τL = (ε∞/εs)τD, of the solvent. The recently developed single-shot spectrostreak picosecond technique was used for the collection of the time-resolved emission spectra.

Research paper thumbnail of Electronic interaction and charge transfer efficiencies in triaromatic donor–acceptor systems. An experimental and theoretical study

Chemical Physics Letters, Jan 2, 1998

To address the issue of electronic interaction between donor (D) and acceptor (A) moieties in int... more To address the issue of electronic interaction between donor (D) and acceptor (A) moieties in intramolecular charge transfer reactions a series of chemically closely related extended pi-systems has been investigated. These compounds contain pyrene and organic methyl ester derivatives connected via a phenyl group. Our steady-state fluorescence studies reveal that only particular compounds exhibit strong charge transfer (CT) emission in solution. To elucidate the experimental results we have performed semiempirical CNDO/S-CI calculations which indicate that the electronic coupling and Coulomb stabilization of the CT state are strongly dependent on the nodal properties of the D/A orbitals.

Research paper thumbnail of Magnetic-field effects on geminate radical-pair recombination

Faraday Discussions of the Chemical Society, 1984

Research paper thumbnail of Magnetic field dependent reaction yields from radical ion pairs linked by a partially rigid aliphatic chain

The Journal of Physical Chemistry, 1993

Research paper thumbnail of Time-Resolved Fluorescence and Solvatochromy of Directly Linked Pyrene−DMA Derivatives in Alcoholic Solution

The Journal of Physical Chemistry B, 2001

... Simone Techert,* † Alexander Wiessner, † Stefan Schmatz, ‡ and Hubert Staerk* †. Max-Planck-I... more ... Simone Techert,* † Alexander Wiessner, † Stefan Schmatz, ‡ and Hubert Staerk* †. Max-Planck-Institut für biophysikalische Chemie, Abteilung Spektroskopie und Photochemische Kinetik, Am Fassberg 11, D-37077 Göttingen ...

Research paper thumbnail of Delayed luminescence of naphthalene in isooctane spectral, lifetime, and magnetic field studies of delayed fluorescence and monomer phosphorescence at 293 K

The Journal of Physical Chemistry, 1991

ABSTRACT

Research paper thumbnail of Intramolecular Electron Hopping in Double Carbazole Molecules Studied by the Fluorescence-Detected Magnetic Field Effect

The Journal of Physical Chemistry a, 1999

ABSTRACT

Research paper thumbnail of Metal-Ion Detection by the Magnetic-Field-Sensitive Fluorescence of Intramolecular Exciplexes Containing Aza-Crown-Ether Moieties as Electron Donor

The Journal of Physical Chemistry A, 1997

Research paper thumbnail of Photophysical Characteristics of Directly Linked Pyrene−Dimethylaniline Derivatives

The Journal of Physical Chemistry A, 2000

ABSTRACT Experimental and theoretical investigations of the spectroscopic properties have been ca... more ABSTRACT Experimental and theoretical investigations of the spectroscopic properties have been carried out on three charge-transfer model systems, covalently linked donor−acceptor compounds of the type pyrene and derivatives of N,N−dimethylaniline (dimethyl(4-pyren-1-ylphenyl)amine (PyDMA), dimethyl(3-methyl-4-pyren-1-ylphenyl)amine (PyMDMA), and (3,5-dimethyl-4-pyren-1-ylphenyl)dimethylamine (PyDMDMA)). Comparing stationary absorption and emission spectra as well as fluorescence lifetimes in different solvents, one can show that small chemical changes such as substitution of ortho-hydrogens by methyl groups on the DMA moiety introduces dramatic effects in spectroscopic and kinetic behavior. On the basis of infrared measurements and quantum chemical calculations, the experiments are interpreted within a statistical framework, with particular emphasis on the discussion of preferred large amplitude motion (twist angle) and pyrene-specific vibronic coupling.

Research paper thumbnail of An Energetic Model for Rapid Mixing

Review of Scientific Instruments, 1969

Research paper thumbnail of E-type delayed fluorescence depolarization, a technique to probe rotational motion in the microsecond range

Journal of Biochemical and Biophysical Methods, 1979

E (eosin)-type delayed fluorescence depolarization studies extend the time range for the measurem... more E (eosin)-type delayed fluorescence depolarization studies extend the time range for the measurement of rotational diffusion to microseconds and ms, thereby allowing investigation of slow rotational movement of macromolecules like membrane proteins. An apparatus is described for the determination of time-dependent anisotropy in this interesting time range. The method has been tested on eosin-labelled cytochrome P-450 incorporated into phospholipid membrane vesicles.

Research paper thumbnail of Photoinduced ion and ketyl radical formation in covalently linked benzophenone—dimethylaniline studied by time-resolved transient absorption spectroscopy with picosecond resolution

Journal of Photochemistry and Photobiology A: Chemistry, 1993

Research paper thumbnail of Electron transfer and magnetic field effects in covalently linked pyrenyl-oligopeptide-dimethylaniline compounds

Journal of Photochemistry and Photobiology A: Chemistry, 1995

The influence of external magnetic fields on the spin dynamics and recombination reaction yield o... more The influence of external magnetic fields on the spin dynamics and recombination reaction yield of radical ion pairs, generated by photoinduced electron transfer between pyrenyl and dimethylaniline linked by an oligopeptide bridge, was studied. From the size and characteristics of the magnetic field effect (MFE), it can be concluded that hydrogen bonds within short peptide chains (here three glycine groups) or with a hydrogen-accepting solvent (acetone) do not seem to affect significantly the chain dynamics.