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BETA
Mucke, Melanie
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Publications (10 of 36) Show all publications
Richter, C., Hollas, D., Saak, C.-M., Foerstel, M., Miteva, T., Mucke, M., . . . Hergenhahn, U. (2018). Competition between proton transfer and intermolecular Coulombic decay in water. Nature Communications, 9, Article ID 4988.
Open this publication in new window or tab >>Competition between proton transfer and intermolecular Coulombic decay in water
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2018 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, article id 4988Article in journal (Refereed) Published
Abstract [en]

Intermolecular Coulombic decay (ICD) is a ubiquitous relaxation channel of electronically excited states in weakly bound systems, ranging from dimers to liquids. As it is driven by electron correlation, it was assumed that it will dominate over more established energy loss mechanisms, for example fluorescence. Here, we use electron-electron coincidence spectroscopy to determine the efficiency of the ICD process after 2a(1) ionization in water clusters. We show that this efficiency is surprisingly low for small water clusters and that it gradually increases to 40-50% for clusters with hundreds of water units. Ab initio molecular dynamics simulations reveal that proton transfer between neighboring water molecules proceeds on the same timescale as ICD and leads to a configuration in which the ICD channel is closed. This conclusion is further supported by experimental results from deuterated water. Combining experiment and theory, we infer an intrinsic ICD lifetime of 12-52 fs for small water clusters.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Physical Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-372335 (URN)10.1038/s41467-018-07501-6 (DOI)000451176100013 ()30478319 (PubMedID)
Funder
EU, Horizon 2020, 705515The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-08-18Bibliographically approved
Fasshauer, E., Förstel, M., Mucke, M., Arion, T. & Hergenhahn, U. (2018). Corrigendum to “Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters” [Chem. Phys. 482 (2017) 226–238]. Chemical Physics, 501, 138-138
Open this publication in new window or tab >>Corrigendum to “Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters” [Chem. Phys. 482 (2017) 226–238]
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2018 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 501, p. 138-138Article in journal (Refereed) Published
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-351597 (URN)10.1016/j.chemphys.2018.01.022 (DOI)000426452900017 ()
Note

Wos title: Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters (vol 482, pg 226, 2017)

Correction to "Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters". In: Chemical Physics, vol. 482 (2017), pages 226–238.

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-05-29Bibliographically approved
Schalk, O., Josefsson, I., Geng, T., Richter, R., Sa'adeh, H., Thomas, R. D. & Mucke, M. (2018). Dissociation kinetics of excited ions: PEPICO measurements of Os3(CO)12 - The 7-35 eV single ionization binding energy region. Journal of Chemical Physics, 148(8), Article ID 084301.
Open this publication in new window or tab >>Dissociation kinetics of excited ions: PEPICO measurements of Os3(CO)12 - The 7-35 eV single ionization binding energy region
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2018 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, no 8, article id 084301Article in journal (Refereed) Published
Abstract [en]

In this article, we study the photoinduced dissociation pathways of a metallocarbonyl, Os-3(CO)(12), in particular the consecutive loss of CO groups. To do so, we performed photoelectron-photoion coincidence (PEPICO) measurements in the single ionization binding energy region from 7 to 35 eV using 45-eV photons. Zero-energy ion appearance energies for the dissociation steps were extracted by modeling the PEPICO data using the statistical adiabatic channel model. Upon ionization to the excited ionic states above 13 eV binding energy, non-statistical behaviorwas observed and assigned to prompt CO loss. Double ionization was found to be dominated by the knockout process with an onset of 20.9 similar to 0.4 eV. The oscillator strength is significantly larger for energies above 26.6 similar to 0.4 eV, corresponding to one electron being ejected from the Os3 center and one from the CO ligands. The cross section for double ionization was found to increase linearly up to 35 eV ionization energy, at which 40% of the generated ions are doubly charged. Published by AIP Publishing.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-351273 (URN)10.1063/1.5018719 (DOI)000426582700015 ()29495778 (PubMedID)
Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Penfold, T., Szlachetko, J., Gawelda, W., Santomauro, F., Britz, A., van Driel, T., . . . Milne, C. (2018). Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy. Paper presented at 256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA. Abstract of Papers of the American Chemical Society, 256
Open this publication in new window or tab >>Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy
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2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-370054 (URN)000447609103665 ()
Conference
256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA
Available from: 2018-12-20 Created: 2018-12-20 Last updated: 2018-12-20Bibliographically approved
Sanchez-Gonzalez, A., Micaelli, P., Olivier, C., Barillot, T. R., Ilchen, M., Lutman, A. A., . . . Marangos, J. P. (2017). Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning. Nature Communications, 8, Article ID 15461.
Open this publication in new window or tab >>Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning
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2017 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 15461Article in journal (Refereed) Published
Abstract [en]

Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-327226 (URN)10.1038/ncomms15461 (DOI)000402745000001 ()28580940 (PubMedID)
Available from: 2017-08-25 Created: 2017-08-25 Last updated: 2017-11-29Bibliographically approved
Wolf, T. J. A., Holzmeier, F., Wagner, I., Berrah, N., Bostedt, C., Bozek, J., . . . Guhr, M. (2017). Observing Femtosecond Fragmentation Using Ultrafast X-ray-Induced Auger Spectra. Applied Sciences, 7(7), Article ID 681.
Open this publication in new window or tab >>Observing Femtosecond Fragmentation Using Ultrafast X-ray-Induced Auger Spectra
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2017 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 7, no 7, article id 681Article in journal (Refereed) Published
Abstract [en]

Molecules often fragment after photoionization in the gas phase. Usually, this process can only be investigated spectroscopically as long as there exists electron correlation between the photofragments. Important parameters, like their kinetic energy after separation, cannot be investigated. We are reporting on a femtosecond time-resolved Auger electron spectroscopy study concerning the photofragmentation dynamics of thymine. We observe the appearance of clearly distinguishable signatures from thymines neutral photofragment isocyanic acid. Furthermore, we observe a time-dependent shift of its spectrum, which we can attribute to the influence of the charged fragment on the Auger electron. This allows us to map our time-dependent dataset onto the fragmentation coordinate. The time dependence of the shift supports efficient transformation of the excess energy gained from photoionization into kinetic energy of the fragments. Our method is broadly applicable to the investigation of photofragmentation processes.

Keywords
ultrafast dynamics, Auger electron spectroscopy, photofragmentation, photochemistry
National Category
Materials Chemistry Physical Sciences
Identifiers
urn:nbn:se:uu:diva-334101 (URN)10.3390/app7070681 (DOI)000407700400038 ()
Funder
Swedish Research CouncilGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of TechnologyKnut and Alice Wallenberg Foundation
Available from: 2017-11-29 Created: 2017-11-29 Last updated: 2017-12-01Bibliographically approved
Wolf, T. J., Myhre, R. H., Cryan, J. P., Coriani, S., Squibb, R. J., Battistoni, A., . . . Guehr, M. (2017). Probing molecular photoinduced dynamics by ultrafast soft x-rays. In: 2017 Conference On Lasers And Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec): . Paper presented at Conference On Lasers And Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec), 2017, June 25-29, Munich, Germany.. IEEE
Open this publication in new window or tab >>Probing molecular photoinduced dynamics by ultrafast soft x-rays
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2017 (English)In: 2017 Conference On Lasers And Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec), IEEE, 2017Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
IEEE, 2017
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-361444 (URN)10.1109/CLEOE-EQEC.2017.8087756 (DOI)000432564601517 ()978-1-5090-6737-4 (ISBN)978-1-5090-6736-7 (ISBN)
Conference
Conference On Lasers And Electro-Optics Europe & European Quantum Electronics Conference (Cleo/Europe-Eqec), 2017, June 25-29, Munich, Germany.
Available from: 2018-09-28 Created: 2018-09-28 Last updated: 2018-10-22Bibliographically approved
Wolf, T. J., Myhre, R. H., Cryan, J. P., Coriani, S., Squibb, R. J., Battistoni, A., . . . Gühr, M. (2017). Probing ultrafast pi pi*/n pi* internal conversion in organic chromophores via K-edge resonant absorption. Nature Communications, 8, Article ID 29.
Open this publication in new window or tab >>Probing ultrafast pi pi*/n pi* internal conversion in organic chromophores via K-edge resonant absorption
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2017 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 29Article in journal (Refereed) Published
Abstract [en]

Many photoinduced processes including photosynthesis and human vision happen in organic molecules and involve coupled femtosecond dynamics of nuclei and electrons. Organic molecules with heteroatoms often possess an important excited-state relaxation channel from an optically allowed pi pi* to a dark n pi* state. The pi pi*/n pi* internal conversion is difficult to investigate, as most spectroscopic methods are not exclusively sensitive to changes in the excited-state electronic structure. Here, we report achieving the required sensitivity by exploiting the element and site specificity of near-edge soft X-ray absorption spectroscopy. As a hole forms in the n orbital during pi pi*/n pi* internal conversion, the absorption spectrum at the heteroatom K-edge exhibits an additional resonance. We demonstrate the concept using the nucleobase thymine at the oxygen K-edge, and unambiguously show that pi pi*/n pi* internal conversion takes place within (60 +/- 30) fs. High-level-coupled cluster calculations confirm the method's impressive electronic structure sensitivity for excited-state investigations.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-329650 (URN)10.1038/s41467-017-00069-7 (DOI)000403876000002 ()28642477 (PubMedID)
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2017-10-03 Created: 2017-10-03 Last updated: 2017-11-29Bibliographically approved
Fasshauer, E., Förstel, M., Mucke, M., Anion, T. & Hergenhahn, U. (2017). Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters. Chemical Physics, 482, 226-238
Open this publication in new window or tab >>Theoretical and experimental investigation of Electron Transfer Mediated Decay in ArKr clusters
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2017 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 482, p. 226-238Article in journal (Refereed) Published
Abstract [en]

We investigate the electronic decay of an Ar 3s(-1) vacancy in medium sized ArKr clusters. The only energetically accessible, radiationless decay mechanism is Electron Transfer Mediated Decay Three (ETMD3). Here, the argon vacancy is filled by an electron from one krypton atom, and the excess energy is transferred to a second krypton atom which consequently emits an electron. For the theoretical calculation of ETMD3 spectra, in a bottom-up approach, we study the dependence of the decay width on the geometry of elementary sets of three atoms, from which any cluster can be composed. We simulate the ETMD3 spectra of medium sized ArKr clusters and compare the resulting spectra to experimental ETMD electron spectra presented earlier (Forstel et al, 2011) and in this work. We show that ETMD3 is the dominating relaxation mechanism for the cases studied here. Experimental secondary electron spectra from ArKr clusters are compared to pure Ar and pure Kr clusters.

Keywords
Electron Transfer Mediated Decay, ETMD3, Heterogeneous noble gas clusters, Electronic decay process, ArKr
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-319138 (URN)10.1016/j.chemphys.2016.09.006 (DOI)000394634700029 ()
Funder
German Research Foundation (DFG), Forschergruppe 1789
Note

Correction in: Chemical Physics, vol. 501, page 138.

Available from: 2017-03-31 Created: 2017-03-31 Last updated: 2018-05-29Bibliographically approved
Zagorodskikh, S., Vapa, M., Vahtras, O., Zhaunerchyk, V., Mucke, M., Eland, J. H. D., . . . Feifel, R. (2016). An experimental and theoretical study of core-valence double ionisation of acetaldehyde (ethanal). Physical Chemistry, Chemical Physics - PCCP, 18(4), 2535-2547
Open this publication in new window or tab >>An experimental and theoretical study of core-valence double ionisation of acetaldehyde (ethanal)
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2016 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 4, p. 2535-2547Article in journal (Refereed) Published
Abstract [en]

Core-valence double ionisation spectra of acetaldehyde (ethanal) are presented at photon energies above the carbon and oxygen 1s ionisation edges, measured by a versatile multi-electron coincidence spectroscopy technique. We use this molecule as a testbed for analyzing core-valence spectra by means of quantum chemical calculations of transition energies. These theoretical approaches range from two simple models, one based on orbital energies corrected by core valence interaction and one based on the equivalent core approximation, to a systematic series of quantum chemical electronic structure methods of increasing sophistication. The two simple models are found to provide a fast orbital interpretation of the spectra, in particular in the low energy parts, while the coverage of the full spectrum is best fulfilled by correlated models. CASPT2 is the most sophisticated model applied, but considering precision as well as computational costs, the single and double excitation configuration interaction model seems to provide the best option to analyze core-valence double hole spectra.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-281987 (URN)10.1039/c5cp05758b (DOI)000369506000030 ()26700657 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationEU, European Research Council, R II 3-CT-2004-506008Swedish National Infrastructure for Computing (SNIC), SNIC 023/07-18
Available from: 2016-04-01 Created: 2016-04-01 Last updated: 2017-11-30Bibliographically approved
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