Here you will find all scientific publications from the group leader, Daniel Horke. Articles and materials written for a more general audience can be found on the Outreach pages. Recent posters from the group are in the gallery!
Filter Publications:
2012
9.
Horke D A, Chatterley A S, Verlet J R R
Effect of Internal Energy on the Repulsive Coulomb Barrier of Polyanions Journal Article
In: Phys. Rev. Lett., vol. 108, no. 8, pp. 083003, 2012.
Links | BibTeX | Altmetric | Tags: photoelectron imaging, Photoelectron spectroscopy, polyanions, velocity-map imaging
@article{Horke:Phys.Rev.Lett.108:083003,
title = {Effect of Internal Energy on the Repulsive Coulomb Barrier of Polyanions},
author = {Daniel A Horke and Adam S Chatterley and Jan R R Verlet},
url = {http://link.aps.org/doi/10.1103/PhysRevLett.108.083003},
doi = {10.1103/PhysRevLett.108.083003},
year = {2012},
date = {2012-02-01},
journal = {Phys. Rev. Lett.},
volume = {108},
number = {8},
pages = {083003},
keywords = {photoelectron imaging, Photoelectron spectroscopy, polyanions, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
8.
Chatterley A S, Horke D A, Verlet J R R
On the Intrinsic Photophysics of Indigo: A Time-Resolved Photoelectron Spectroscopy Study of the Indigo Carmine Dianion Journal Article
In: Phys. Chem. Chem. Phys., vol. 14, no. 46, pp. 16155, 2012.
Links | BibTeX | Altmetric | Tags: Anion spectroscopy, dynamics, Photoelectron spectroscopy, polyanions, velocity-map imaging
@article{Chatterley:Phys.Chem.Chem.Phys.14:16155,
title = {On the Intrinsic Photophysics of Indigo: A Time-Resolved Photoelectron Spectroscopy Study of the Indigo Carmine Dianion},
author = {Adam S Chatterley and Daniel A Horke and Jan R R Verlet},
url = {http://xlink.rsc.org/?DOI=c2cp43275g},
doi = {10.1039/c2cp43275g},
year = {2012},
date = {2012-01-01},
journal = {Phys. Chem. Chem. Phys.},
volume = {14},
number = {46},
pages = {16155},
keywords = {Anion spectroscopy, dynamics, Photoelectron spectroscopy, polyanions, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
7.
Horke D A, Verlet J R R
Photoelectron Spectroscopy of the Model GFP Chromophore Anion Journal Article
In: Phys. Chem. Chem. Phys., vol. 14, no. 24, pp. 8511–8515, 2012.
Abstract | Links | BibTeX | Altmetric | Tags: Anion spectroscopy, Photoelectron spectroscopy
@article{Horke:Phys.Chem.Chem.Phys.14:8511,
title = {Photoelectron Spectroscopy of the Model GFP Chromophore Anion},
author = {Daniel A Horke and Jan R R Verlet},
url = {http://xlink.rsc.org/?DOI=c2cp40880e},
doi = {10.1039/c2cp40880e},
year = {2012},
date = {2012-01-01},
journal = {Phys. Chem. Chem. Phys.},
volume = {14},
number = {24},
pages = {8511--8515},
abstract = {A photoelectron spectroscopy study of the anionic model chromophore of the green fluorescent protein is presented. From the photoelectron spectra taken at 3.496 eV, 4.62 eV, and 6.15 eV the vertical and adiabatic detachment energies are determined to be 2.8 +/- 0.1 eV and 2.6 +/- 0.2 eV, respectively. The vertical detachment energy is higher than the S1 ? S0 absorption maximum (2.57 eV) and indicates that the S1 state is bound with respect to electron detachment in the Franck-Condon region. The photoelectron spectrum taken at 6.15 eV, together with TD-DFT calculations, are used to assign a number of excited states in the neutral radical that correspond to electron loss from occupied orbitals in the anion. The photoelectron spectrum at 2.58 eV shows evidence for electrons formed by thermionic emission, suggesting that internal conversion is the dominant relaxation pathway following S1 ? S0 excitation.},
keywords = {Anion spectroscopy, Photoelectron spectroscopy},
pubstate = {published},
tppubtype = {article}
}
A photoelectron spectroscopy study of the anionic model chromophore of the green fluorescent protein is presented. From the photoelectron spectra taken at 3.496 eV, 4.62 eV, and 6.15 eV the vertical and adiabatic detachment energies are determined to be 2.8 +/- 0.1 eV and 2.6 +/- 0.2 eV, respectively. The vertical detachment energy is higher than the S1 ? S0 absorption maximum (2.57 eV) and indicates that the S1 state is bound with respect to electron detachment in the Franck-Condon region. The photoelectron spectrum taken at 6.15 eV, together with TD-DFT calculations, are used to assign a number of excited states in the neutral radical that correspond to electron loss from occupied orbitals in the anion. The photoelectron spectrum at 2.58 eV shows evidence for electrons formed by thermionic emission, suggesting that internal conversion is the dominant relaxation pathway following S1 ? S0 excitation.
6.
Horke D A, Roberts G M, Lecointre J, Verlet J R R
Velocity-Map Imaging at Low Extraction Fields. Journal Article
In: Rev. Sci. Instr., vol. 83, no. 6, pp. 063101, 2012.
Abstract | Links | BibTeX | Altmetric | Tags: experimental design, photoelectron imaging, velocity-map imaging
@article{Horke:Rev.Sci.Instr.83:063101,
title = {Velocity-Map Imaging at Low Extraction Fields.},
author = {Daniel A Horke and Gareth M Roberts and Julien Lecointre and Jan R R Verlet},
url = {http://link.aip.org/link/RSINAK/v83/i6/p063101/s1\&Agg=doi},
doi = {10.1063/1.4724311},
year = {2012},
date = {2012-01-01},
journal = {Rev. Sci. Instr.},
volume = {83},
number = {6},
pages = {063101},
abstract = {We present a velocity-map imaging (VMI) setup for photoelectron imaging that utilizes low electric extraction fields. This avoids any complications that could arise from electrostatic interactions between the extraction field and the molecular properties that are probed and has a minimal effect on the trajectory of ions in ion beam experiments. By using an attractive potential supplied to the detector, and keeping the electrodes at ground (zero) potential, we show that fringe fields between the VMI arrangement and the vacuum chamber can be eliminated, which is important in experiments on ions.},
keywords = {experimental design, photoelectron imaging, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
We present a velocity-map imaging (VMI) setup for photoelectron imaging that utilizes low electric extraction fields. This avoids any complications that could arise from electrostatic interactions between the extraction field and the molecular properties that are probed and has a minimal effect on the trajectory of ions in ion beam experiments. By using an attractive potential supplied to the detector, and keeping the electrodes at ground (zero) potential, we show that fringe fields between the VMI arrangement and the vacuum chamber can be eliminated, which is important in experiments on ions.
5.
Horke D A
Femtosecond Photoelectron Imaging of Anions PhD Thesis
2012.
Links | BibTeX | Tags: alignment, Anion spectroscopy, experimental design, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, polyanions, velocity-map imaging
@phdthesis{Horke:undefined:,
title = {Femtosecond Photoelectron Imaging of Anions},
author = {Daniel A Horke},
url = {http://etheses.dur.ac.uk/5950/},
year = {2012},
date = {2012-01-01},
address = {Durham},
keywords = {alignment, Anion spectroscopy, experimental design, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, polyanions, velocity-map imaging},
pubstate = {published},
tppubtype = {phdthesis}
}
2011
4.
Horke D A, Roberts G M, Verlet J R R
Excited States in Electron-Transfer Reaction Products: Ultrafast Relaxation Dynamics of an Isolated Acceptor Radical Anion Journal Article
In: J. Phys. Chem. A, vol. 115, no. 30, pp. 8369–8374, 2011.
Links | BibTeX | Altmetric | Tags: Anion spectroscopy, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy
@article{Horke:J.Phys.Chem.A115:8369,
title = {Excited States in Electron-Transfer Reaction Products: Ultrafast Relaxation Dynamics of an Isolated Acceptor Radical Anion},
author = {Daniel A Horke and Gareth M Roberts and Jan R R Verlet},
url = {http://dx.doi.org/10.1021/jp2038202},
doi = {10.1021/jp2038202},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
journal = {J. Phys. Chem. A},
volume = {115},
number = {30},
pages = {8369--8374},
keywords = {Anion spectroscopy, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy},
pubstate = {published},
tppubtype = {article}
}
3.
Horke D A, Verlet J R R
Time-Resolved Photoelectron Imaging of the Chloranil Radical Anion: Ultrafast Relaxation of Electronically Excited Electron Acceptor States Journal Article
In: Phys. Chem. Chem. Phys., vol. 13, no. 43, pp. 19546–19552, 2011.
Abstract | Links | BibTeX | Altmetric | Tags: Anion spectroscopy, dynamics, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, velocity-map imaging
@article{Horke:Phys.Chem.Chem.Phys.13:19546,
title = {Time-Resolved Photoelectron Imaging of the Chloranil Radical Anion: Ultrafast Relaxation of Electronically Excited Electron Acceptor States},
author = {Daniel A Horke and Jan R R Verlet},
url = {http://xlink.rsc.org/?DOI=c1cp22237f},
doi = {10.1039/c1cp22237f},
year = {2011},
date = {2011-01-01},
journal = {Phys. Chem. Chem. Phys.},
volume = {13},
number = {43},
pages = {19546--19552},
abstract = {The spectroscopy and dynamics of near-threshold excited states of the isolated chloranil radical anion are investigated using photoelectron imaging. The photoelectron images taken at 480 nm clearly indicate resonance-enhanced photodetachment via a bound electronic excited state. Time-resolved photoelectron imaging reveals that the excited state rapidly decays on a timescale of 130 fs via internal conversion. The ultrafast relaxation dynamics of excited states near threshold are pertinent to common electron acceptor molecules based on the quinone moiety and may serve as doorway states that enable efficient electron transfer in the highly exergonic inverted regime, despite the presence of large free energy barriers.},
keywords = {Anion spectroscopy, dynamics, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
The spectroscopy and dynamics of near-threshold excited states of the isolated chloranil radical anion are investigated using photoelectron imaging. The photoelectron images taken at 480 nm clearly indicate resonance-enhanced photodetachment via a bound electronic excited state. Time-resolved photoelectron imaging reveals that the excited state rapidly decays on a timescale of 130 fs via internal conversion. The ultrafast relaxation dynamics of excited states near threshold are pertinent to common electron acceptor molecules based on the quinone moiety and may serve as doorway states that enable efficient electron transfer in the highly exergonic inverted regime, despite the presence of large free energy barriers.
2010
2.
Lecointre J, Roberts G M, Horke D A, Verlet J R R
Ultrafast Relaxation Dynamics Observed Through Time-Resolved Photoelectron Angular Distributions textdagger Journal Article
In: J. Phys. Chem. A, vol. 114, no. 42, pp. 11216–11224, 2010.
Abstract | Links | BibTeX | Altmetric | Tags: Anion spectroscopy, experimental design, photoelectron imaging, velocity-map imaging
@article{Lecointre:J.Phys.Chem.A114:11216,
title = {Ultrafast Relaxation Dynamics Observed Through Time-Resolved Photoelectron Angular Distributions textdagger},
author = {Julien Lecointre and Gareth M Roberts and Daniel A Horke and Jan R R Verlet},
url = {http://pubs.acs.org/doi/abs/10.1021/jp1028855},
doi = {10.1021/jp1028855},
year = {2010},
date = {2010-10-01},
journal = {J. Phys. Chem. A},
volume = {114},
number = {42},
pages = {11216--11224},
abstract = {Time-resolved photoelectron imaging of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion is presented. Photoelectron angular distributions (PADs) are qualitatively analyzed in terms of the simple s-p model that is based on symmetry arguments. The internal conversion dynamics from the first excited state (1(2)B(3u)) to the ground state ((2)B(2g)) may be observed through temporal changes in the PADs of the spectrally overlapping photoelectron features arising from photodetachment of the ground state and the excited state. A formulism for extracting the population dynamics from the $beta$(2) anisotropy parameter of overlapping spectroscopic features is presented. This is used to extract the lifetime of the first excited state, which is in good agreement with that observed in the time-resolved photoelectron spectra.},
keywords = {Anion spectroscopy, experimental design, photoelectron imaging, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
Time-resolved photoelectron imaging of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion is presented. Photoelectron angular distributions (PADs) are qualitatively analyzed in terms of the simple s-p model that is based on symmetry arguments. The internal conversion dynamics from the first excited state (1(2)B(3u)) to the ground state ((2)B(2g)) may be observed through temporal changes in the PADs of the spectrally overlapping photoelectron features arising from photodetachment of the ground state and the excited state. A formulism for extracting the population dynamics from the $beta$(2) anisotropy parameter of overlapping spectroscopic features is presented. This is used to extract the lifetime of the first excited state, which is in good agreement with that observed in the time-resolved photoelectron spectra.
1.
Roberts G M, Lecointre J, Horke D A, Verlet J R R
Spectroscopy and Dynamics of the 7,7,8,8-Tetracyanoquinodimethane Radical Anion. Journal Article
In: Phys. Chem. Chem. Phys., vol. 12, no. 23, pp. 6226–6232, 2010.
Abstract | Links | BibTeX | Altmetric | Tags: Anion spectroscopy, dynamics, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, velocity-map imaging
@article{Roberts:Phys.Chem.Chem.Phys.12:6226,
title = {Spectroscopy and Dynamics of the 7,7,8,8-Tetracyanoquinodimethane Radical Anion.},
author = {Gareth M Roberts and Julien Lecointre and Daniel A Horke and Jan R R Verlet},
url = {http://dx.doi.org/10.1039/c001438a},
doi = {10.1039/c001438a},
year = {2010},
date = {2010-01-01},
journal = {Phys. Chem. Chem. Phys.},
volume = {12},
number = {23},
pages = {6226--6232},
abstract = {The photoelectron spectrum of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion has been measured at 3.1 eV. Additionally, the ultrafast relaxation dynamics of the first excited state (1(2)B(3u)) of TCNQ(-) have been studied using time-resolved photoelectron spectroscopy, which reveals that it undergoes internal conversion back to the ground state ((2)B(2g)) with an associated lifetime of 650 fs and shows evidence of coherent nuclear motion. From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. - Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. - Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. - Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. - Roberts, Gareth M; Lecointre, Julien; Horke, Daniel A; Verlet, Jan R R )},
keywords = {Anion spectroscopy, dynamics, Non-adiabatic dynamics, photoelectron imaging, Photoelectron spectroscopy, velocity-map imaging},
pubstate = {published},
tppubtype = {article}
}
The photoelectron spectrum of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion has been measured at 3.1 eV. Additionally, the ultrafast relaxation dynamics of the first excited state (1(2)B(3u)) of TCNQ(-) have been studied using time-resolved photoelectron spectroscopy, which reveals that it undergoes internal conversion back to the ground state ((2)B(2g)) with an associated lifetime of 650 fs and shows evidence of coherent nuclear motion. From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. – Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. – Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. – Roberts, Gareth M; Lecointre, Julien; Horke, Daniel a; Verlet, Jan R R ) From Duplicate 1 ( Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethane radical anion. – Roberts, Gareth M; Lecointre, Julien; Horke, Daniel A; Verlet, Jan R R )