News
Our latest paper using coincidence double-VMI imaging to distinguish neutral and ionic multiphoton dissociation channels in molecular oxygen is out now in @JPhysChem A - well done Ana! https://doi.org/10.1021/acs.jpca.2c06707
Yerbolat joins the group as a PostDoc to work on your NWO-funded project on electron-driven reactions - Welcome Yerbolat!
Our latest paper comparing continuous and pulsed laser-based desorption (LIAD) methods is out now in Eur.Phys.J. D - well done Siwen! https://bit.ly/3cYM5tc
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Recent Publications
Caballo, Ana; Huits, Anders J. T. M.; Parker, David H.; Horke, Daniel A.
Disentangling Multiphoton Ionization and Dissociation Channels in Molecular Oxygen Using Photoelectron–Photoion Coincidence Imaging Journal Article
In: J. Phys. Chem. A, vol. 127, no. 1, pp. 92–98, 2023, ISSN: 1089-5639, 1520-5215.
@article{caballoDisentanglingMultiphotonIonization2023,
title = {Disentangling Multiphoton Ionization and Dissociation Channels in Molecular Oxygen Using Photoelectron\textendashPhotoion Coincidence Imaging},
author = {Ana Caballo and Anders J. T. M. Huits and David H. Parker and Daniel A. Horke},
url = {https://pubs.acs.org/doi/10.1021/acs.jpca.2c06707},
doi = {10.1021/acs.jpca.2c06707},
issn = {1089-5639, 1520-5215},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {J. Phys. Chem. A},
volume = {127},
number = {1},
pages = {92--98},
abstract = {Multiphoton excitation of molecular oxygen in the 392-408 nm region is studied using a tunable femtosecond laser coupled with a double velocity map imaging photoelectron- photoion coincidence spectrometer. The laser intensity is held at $\leqsim$1 TW/cm2 to ensure excitation in the perturbative regime, where the possibility of resonance enhanced multiphoton ionization (REMPI) can be investigated. O2+ production is found to be resonance enhanced around 400 nm via three-photon excitation to the e$'$3$Delta$u(v = 0) state, similar to results from REMPI studies using nanosecond dye lasers. O+ production reaches 7% of the total ion yield around 405 nm due to two processes: autoionization following five-photon excitation of O2, producing O2+(X(v)) in a wide range of vibrational states followed by two- or three-photon dissociation, or six-photon excitation to a superexcited O2** state followed by neutral dissociation and subsequent ionization of the electronically excited O atom. Coincidence detection is shown to be crucial in identifying these competing pathways.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Multiphoton excitation of molecular oxygen in the 392-408 nm region is studied using a tunable femtosecond laser coupled with a double velocity map imaging photoelectron- photoion coincidence spectrometer. The laser intensity is held at $łeqsim$1 TW/cm2 to ensure excitation in the perturbative regime, where the possibility of resonance enhanced multiphoton ionization (REMPI) can be investigated. O2+ production is found to be resonance enhanced around 400 nm via three-photon excitation to the e$'$3$Delta$u(v = 0) state, similar to results from REMPI studies using nanosecond dye lasers. O+ production reaches 7% of the total ion yield around 405 nm due to two processes: autoionization following five-photon excitation of O2, producing O2+(X(v)) in a wide range of vibrational states followed by two- or three-photon dissociation, or six-photon excitation to a superexcited O2** state followed by neutral dissociation and subsequent ionization of the electronically excited O atom. Coincidence detection is shown to be crucial in identifying these competing pathways.
Wang, Siwen; Abma, Grite L.; Krüger, Peter; Roij, Andre; Balster, Michiel; Janssen, Niek; Horke, Daniel A.
Comparing Pulsed and Continuous Laser-Induced Acoustic Desorption (LIAD) as Sources for Intact Biomolecules Journal Article
In: Eur. Phys. J. D, vol. 76, no. 7, pp. 128, 2022, ISSN: 1434-6060, 1434-6079.
@article{wangComparingPulsedContinuous2022,
title = {Comparing Pulsed and Continuous Laser-Induced Acoustic Desorption (LIAD) as Sources for Intact Biomolecules},
author = {Siwen Wang and Grite L. Abma and Peter Kr\"{u}ger and Andre Roij and Michiel Balster and Niek Janssen and Daniel A. Horke},
url = {https://link.springer.com/10.1140/epjd/s10053-022-00459-7},
doi = {10.1140/epjd/s10053-022-00459-7},
issn = {1434-6060, 1434-6079},
year = {2022},
date = {2022-07-01},
urldate = {2022-07-25},
journal = {Eur. Phys. J. D},
volume = {76},
number = {7},
pages = {128},
abstract = {A major obstacle to the gas-phase study of larger (bio)molecular systems is the vaporisation step, that is, the introduction of intact sample molecules into the gas-phase. A promising approach is the use of laser-induced acoustic desorption (LIAD) sources, which have been demonstrated using both nanosecond pulsed and continuous desorption lasers. We directly compare here both approaches for the first time under otherwise identical conditions using adenine as a prototypical biological molecule, and study the produced molecular plumes using femtosecond multiphoton ionisation. We observe different desorption mechanisms at play for the two different desorption laser sources; however, we find no evidence in either case that the desorption process leads to fragmentation of the target molecule unless excessive desorption energy is applied. This makes LIAD a powerful approach for techniques that require high density and high purity samples in the gas-phase, such as ultrafast dynamics studies or diffraction experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A major obstacle to the gas-phase study of larger (bio)molecular systems is the vaporisation step, that is, the introduction of intact sample molecules into the gas-phase. A promising approach is the use of laser-induced acoustic desorption (LIAD) sources, which have been demonstrated using both nanosecond pulsed and continuous desorption lasers. We directly compare here both approaches for the first time under otherwise identical conditions using adenine as a prototypical biological molecule, and study the produced molecular plumes using femtosecond multiphoton ionisation. We observe different desorption mechanisms at play for the two different desorption laser sources; however, we find no evidence in either case that the desorption process leads to fragmentation of the target molecule unless excessive desorption energy is applied. This makes LIAD a powerful approach for techniques that require high density and high purity samples in the gas-phase, such as ultrafast dynamics studies or diffraction experiments.
Abma, Grite L.; Kleuskens, Dries; Wang, Siwen; Balster, Michiel; Roij, Andre; Janssen, Niek; Horke, Daniel A.
Single-Color Isomer-Resolved Spectroscopy Journal Article
In: The Journal of Physical Chemistry A, vol. 126, pp. 3811–3815, 2022.
@article{abmaSinglecolorIsomerresolvedSpectroscopy2022,
title = {Single-Color Isomer-Resolved Spectroscopy},
author = {Grite L. Abma and Dries Kleuskens and Siwen Wang and Michiel Balster and Andre Roij and Niek Janssen and Daniel A. Horke},
url = {https://doi.org/10.1021/acs.jpca.2c02277},
doi = {10.1021/acs.jpca.2c02277},
year = {2022},
date = {2022-06-01},
urldate = {2022-06-01},
journal = {The Journal of Physical Chemistry A},
volume = {126},
pages = {3811\textendash3815},
abstract = {Structural isomers, such as conformers or tautomers, are
of significant importance across chemistry and biology, as they can have
different functionalities. In gas-phase experiments using molecular
beams, formation of many different isomers cannot be prevented, and
their presence significantly complicates the assignment of spectral lines.
Current isomer-resolved spectroscopic techniques heavily rely on
theoretical calculations or make use of elaborate double-resonance
schemes. We show here that isomer-resolved spectroscopy can also be
performed using a single tunable laser. In particular, we demonstrate
single-color isomer-resolved spectroscopy by utilizing electrostatic
deflection to spatially separate the isomers. We show that for 3-
aminophenol we can spatially separate the syn and anti conformers and
use these pure samples to perform high-resolution REMPI spectroscopy, making the assignment of transitions to a particular isomer trivial, without any additional a priori information. This approach allows one to add isomer specificity to any molecular-beam-based experiment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Structural isomers, such as conformers or tautomers, are
of significant importance across chemistry and biology, as they can have
different functionalities. In gas-phase experiments using molecular
beams, formation of many different isomers cannot be prevented, and
their presence significantly complicates the assignment of spectral lines.
Current isomer-resolved spectroscopic techniques heavily rely on
theoretical calculations or make use of elaborate double-resonance
schemes. We show here that isomer-resolved spectroscopy can also be
performed using a single tunable laser. In particular, we demonstrate
single-color isomer-resolved spectroscopy by utilizing electrostatic
deflection to spatially separate the isomers. We show that for 3-
aminophenol we can spatially separate the syn and anti conformers and
use these pure samples to perform high-resolution REMPI spectroscopy, making the assignment of transitions to a particular isomer trivial, without any additional a priori information. This approach allows one to add isomer specificity to any molecular-beam-based experiment.
of significant importance across chemistry and biology, as they can have
different functionalities. In gas-phase experiments using molecular
beams, formation of many different isomers cannot be prevented, and
their presence significantly complicates the assignment of spectral lines.
Current isomer-resolved spectroscopic techniques heavily rely on
theoretical calculations or make use of elaborate double-resonance
schemes. We show here that isomer-resolved spectroscopy can also be
performed using a single tunable laser. In particular, we demonstrate
single-color isomer-resolved spectroscopy by utilizing electrostatic
deflection to spatially separate the isomers. We show that for 3-
aminophenol we can spatially separate the syn and anti conformers and
use these pure samples to perform high-resolution REMPI spectroscopy, making the assignment of transitions to a particular isomer trivial, without any additional a priori information. This approach allows one to add isomer specificity to any molecular-beam-based experiment.