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:
2019
3.
Bieker H, Onvlee J, Johny M, He L, Kierspel T, Trippel S, Horke D A, Küpper J
Pure Molecular Beam of Water Dimer Journal Article
In: J. Phys. Chem. A, vol. 123, no. 34, pp. 7486–7490, 2019, ISSN: 1089-5639.
Abstract | Links | BibTeX | Altmetric | Tags: clusters, Control, electrostatic deflector, strong-field processes
@article{Bieker:J.Phys.Chem.A123:7486,
title = {Pure Molecular Beam of Water Dimer},
author = {Helen Bieker and Jolijn Onvlee and Melby Johny and Lanhai He and Thomas Kierspel and Sebastian Trippel and Daniel Alfred Horke and Jochen K\"{u}pper},
url = {https://doi.org/10.1021/acs.jpca.9b06460},
doi = {10.1021/acs.jpca.9b06460},
issn = {1089-5639},
year = {2019},
date = {2019-07-01},
urldate = {2019-08-07},
journal = {J. Phys. Chem. A},
volume = {123},
number = {34},
pages = {7486--7490},
abstract = {Spatial separation of water dimers from water monomers and larger water-clusters through the electric deflector is presented. A beam of water dimers with $93textasciitildetextbackslash%$ purity and a rotational temperature of $1.5textasciitilde$K was obtained. Following strong-field ionization using a 35textasciitilde fs laser pulse with a wavelength centered around 800textasciitilde nm and a peak intensity of $10^14textasciitildetextbackslash Wpcmcm$ we observed proton transfer and $46textasciitildetextbackslash%$ of ionized water dimers broke apart into hydronium ions textbackslash HHHOp and neutral OH.},
keywords = {clusters, Control, electrostatic deflector, strong-field processes},
pubstate = {published},
tppubtype = {article}
}
Spatial separation of water dimers from water monomers and larger water-clusters through the electric deflector is presented. A beam of water dimers with $93textasciitildetextbackslash%$ purity and a rotational temperature of $1.5textasciitilde$K was obtained. Following strong-field ionization using a 35textasciitilde fs laser pulse with a wavelength centered around 800textasciitilde nm and a peak intensity of $10^14textasciitildetextbackslash Wpcmcm$ we observed proton transfer and $46textasciitildetextbackslash%$ of ionized water dimers broke apart into hydronium ions textbackslash HHHOp and neutral OH.
2015
2.
Chang Y, Horke D A, Trippel S, Küpper J
Spatially-Controlled Complex Molecules and Their Applications Journal Article
In: Int. Rev. Phys. Chem., vol. 34, no. 4, pp. 557–590, 2015.
Links | BibTeX | Altmetric | Tags: clusters, electrostatic deflector, Isomer-effects, review
@article{Chang:Int.Rev.Phys.Chem.34:557,
title = {Spatially-Controlled Complex Molecules and Their Applications},
author = {Yuan-Pin Chang and Daniel A Horke and Sebastian Trippel and Jochen K\"{u}pper},
url = {http://www.tandfonline.com/doi/full/10.1080/0144235X.2015.1077838},
doi = {10.1080/0144235X.2015.1077838},
year = {2015},
date = {2015-10-01},
journal = {Int. Rev. Phys. Chem.},
volume = {34},
number = {4},
pages = {557--590},
keywords = {clusters, electrostatic deflector, Isomer-effects, review},
pubstate = {published},
tppubtype = {article}
}
2014
1.
Horke D, Trippel S, Chang Y, Stern S, Mullins T, Kierspel T, pper J K
Spatial Separation of Molecular Conformers and Clusters Journal Article
In: JoVE, no. 83, pp. e51137, 2014, ISSN: 1940-087X.
Abstract | Links | BibTeX | Tags: clusters, Control, electrostatic deflector, Isomer-effects
@article{Horke:JoVE:e51137,
title = {Spatial Separation of Molecular Conformers and Clusters},
author = {Daniel Horke and Sebastian Trippel and Yuan-Pin Chang and Stephan Stern and Terry Mullins and Thomas Kierspel and Jochen K 252 pper},
url = {http://www.jove.com/video/51137},
issn = {1940-087X},
year = {2014},
date = {2014-01-01},
journal = {JoVE},
number = {83},
pages = {e51137},
abstract = {Gas-phase molecular physics and physical chemistry experiments commonly use supersonic expansions through pulsed valves for the production of cold molecular beams. However, these beams often contain multiple conformers and clusters, even at low rotational temperatures. We present an experimental methodology that allows the spatial separation of these constituent parts of a molecular beam expansion. Using an electric deflector the beam is separated by its mass-to-dipole moment ratio, analogous to a bender or an electric sector mass spectrometer spatially dispersing charged molecules on the basis of their mass-to-charge ratio. This deflector exploits the Stark effect in an inhomogeneous electric field and allows the separation of individual species of polar neutral molecules and clusters. It furthermore allows the selection of the coldest part of a molecular beam, as low-energy rotational quantum states generally experience the largest deflection. Different structural isomers (conformers) of a species can be separated due to the different arrangement of functional groups, which leads to distinct dipole moments. These are exploited by the electrostatic deflector for the production of a conformationally pure sample from a molecular beam. Similarly, specific cluster stoichiometries can be selected, as the mass and dipole moment of a given cluster depends on the degree of solvation around the parent molecule. This allows experiments on specific cluster sizes and structures, enabling the systematic study of solvation of neutral molecules.},
keywords = {clusters, Control, electrostatic deflector, Isomer-effects},
pubstate = {published},
tppubtype = {article}
}
Gas-phase molecular physics and physical chemistry experiments commonly use supersonic expansions through pulsed valves for the production of cold molecular beams. However, these beams often contain multiple conformers and clusters, even at low rotational temperatures. We present an experimental methodology that allows the spatial separation of these constituent parts of a molecular beam expansion. Using an electric deflector the beam is separated by its mass-to-dipole moment ratio, analogous to a bender or an electric sector mass spectrometer spatially dispersing charged molecules on the basis of their mass-to-charge ratio. This deflector exploits the Stark effect in an inhomogeneous electric field and allows the separation of individual species of polar neutral molecules and clusters. It furthermore allows the selection of the coldest part of a molecular beam, as low-energy rotational quantum states generally experience the largest deflection. Different structural isomers (conformers) of a species can be separated due to the different arrangement of functional groups, which leads to distinct dipole moments. These are exploited by the electrostatic deflector for the production of a conformationally pure sample from a molecular beam. Similarly, specific cluster stoichiometries can be selected, as the mass and dipole moment of a given cluster depends on the degree of solvation around the parent molecule. This allows experiments on specific cluster sizes and structures, enabling the systematic study of solvation of neutral molecules.