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Publications (10 of 76) Show all publications
Travnikova, O., Patanen, M., Söderström, J., Lindblad, A., Kas, J. J., Yila, F. D., . . . Saethre, L. J. (2019). Energy-Dependent Relative Cross Sections in Carbon 1s Photoionization: Separation of Direct Shake and Inelastic Scattering Effects in Single Molecules. Paper presented at 64th Pacific Conference on Spectroscopy and Dynamics (PCSD), JAN 19-22, 2017, Pacific Grove, CA. Journal of Physical Chemistry A, 123(35), 7619-7635
Open this publication in new window or tab >>Energy-Dependent Relative Cross Sections in Carbon 1s Photoionization: Separation of Direct Shake and Inelastic Scattering Effects in Single Molecules
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2019 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, no 35, p. 7619-7635Article in journal (Refereed) Published
Abstract [en]

We demonstrate that the possibility of monitoring relative photoionization cross sections over a large photon energy range allows us to study and disentangle shake processes and intramolecular inelastic scattering effects. In this gas-phase study, relative intensities of the carbon 1s photoelectron lines from chemically inequivalent carbon atoms in the same molecule have been measured as a function of the incident photon energy in the range of 300-6000 eV. We present relative cross sections for the chemically shifted carbon 1s lines in the photoelectron spectra of ethyl trifluoroacetate (the "ESCA" molecule). The results are compared with those of methyl trifluoroacetate and S-ethyl trifluorothioacetate as well as a series of chloro-substituted ethanes and 2-butyne. In the soft X-ray energy range, the cross sections show an extended X-ray absorption fine structure type of wiggles, as was previously observed for a series of chloroethanes. The oscillations are damped in the hard X-ray energy range, but deviations of cross-section ratios from stoichiometry persist, even at high energies. The current findings are supported by theoretical calculations based on a multiple scattering model. The use of soft and tender X-rays provides a more complete picture of the dominant processes accompanying photoionization. Such processes reduce the main photoelectron line intensities by 20-60%. Using both energy ranges enabled us to discern the process of intramolecular inelastic scattering of the outgoing electron, whose significance is otherwise difficult to assess for isolated molecules. This effect relates to the notion of the inelastic mean free path commonly used in photoemission studies of clusters and condensed matter.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Theoretical Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-394685 (URN)10.1021/acs.jpca.9b05063 (DOI)000484884200011 ()31386367 (PubMedID)
Conference
64th Pacific Conference on Spectroscopy and Dynamics (PCSD), JAN 19-22, 2017, Pacific Grove, CA
Funder
Knut and Alice Wallenberg Foundation
Available from: 2019-10-30 Created: 2019-10-30 Last updated: 2019-10-30Bibliographically approved
Svensson, S., Siegbahn, H., Nordgren, J. & Mårtensson, N. (2018). Biographical item: "Prof. Carl Nordling 1931-2016 Obituary" in Journal Of Electron Spectroscopy And Related Phenomena, vol 224, Special Issue: SI, pp 107-108. , 224
Open this publication in new window or tab >>Biographical item: "Prof. Carl Nordling 1931-2016 Obituary" in Journal Of Electron Spectroscopy And Related Phenomena, vol 224, Special Issue: SI, pp 107-108
2018 (English)Other (Other (popular science, discussion, etc.))
Series
Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-357035 (URN)10.1016/j.elspec.2016.12.008 (DOI)000428825400017 ()
Note

Minnesord (Obituary)

Available from: 2018-08-10 Created: 2018-08-10 Last updated: 2018-08-10Bibliographically approved
Kuehn, D., Sorgenfrei, F., Giangrisostomi, E., Jay, R., Musazay, A., Ovsyannikov, R., . . . Foehlisch, A. (2018). Capabilities of Angle Resolved Time of Flight electron spectroscopy with the 60 degrees wide angle acceptance lens. Journal of Electron Spectroscopy and Related Phenomena, 224, 45-50
Open this publication in new window or tab >>Capabilities of Angle Resolved Time of Flight electron spectroscopy with the 60 degrees wide angle acceptance lens
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2018 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 45-50Article in journal (Refereed) Published
Abstract [en]

The simultaneous detection of energy, momentum and temporal information in electron spectroscopy is the key aspect to enhance the detection efficiency in order to broaden the range of scientific applications. Employing a novel 60 degrees wide angle acceptance lens system, based on an additional accelerating electron optical element, leads to a significant enhancement in transmission over the previously employed 30 degrees electron lenses. Due to the performance gain, optimized capabilities for time resolved electron spectroscopy and other high transmission applications with pulsed ionizing radiation have been obtained. The energy resolution and transmission have been determined experimentally utilizing BESSY II as a photon source. Four different and complementary lens modes have been characterized. (C) 2017 The Authors. Published by Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Artof, Electron spectroscopy, Wide angle, Time of flight, Energy resolution, Synchrotron
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-351685 (URN)10.1016/j.elspec.2017.06.008 (DOI)000428825400009 ()
Funder
Swedish Research CouncilEU, FP7, Seventh Framework Programme, 321319Carl Tryggers foundation EU, Horizon 2020, 669531 EDAX
Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Giangrisostomi, E., Ovsyannikov, R., Sorgenfrei, F., Zhang, T., Lindblad, A., Sassa, Y., . . . Foehlisch, A. (2018). Low Dose Photoelectron Spectroscopy at BESSY II: Electronic structure of matter in its native state. Journal of Electron Spectroscopy and Related Phenomena, 224, 68-78
Open this publication in new window or tab >>Low Dose Photoelectron Spectroscopy at BESSY II: Electronic structure of matter in its native state
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2018 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 68-78Article in journal (Refereed) Published
Abstract [en]

The implementation of a high-transmission, angular-resolved time-of-Right electron spectrometer with a 1.25 MHz pulse selector at the PM4 soft X-ray dipole beamline of the synchrotron BESSY II creates unique capabilities to inquire electronic structure via photoelectron spectroscopy with a minimum of radiation dose. Solid-state samples can be prepared and characterized with standard UHV techniques and rapidly transferred from various preparation chambers to a 4-axis temperature-controlled measurement stage. A synchronized MHz laser system enables excited-state characterization and dynamical studies starting from the picosecond timescale. This article introduces the principal characteristics of the PM4 beamline and LowDosePES end-station. Recent results from graphene, an organic hole transport material for solar cells and the transition metal dichalcogenide MoS2 are presented to demonstrate the instrument performances. (C) 2017 The Authors. Published by Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-351686 (URN)10.1016/j.elspec.2017.05.011 (DOI)000428825400012 ()
Funder
Swedish Research Council, 2014-6463EU, FP7, Seventh Framework Programme, 321319
Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Cappel, U. B., Svanström, S., Lanzilotto, V., Johansson, F. O. L., Aitola, K., Philippe, B., . . . Rensmo, H. (2017). Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells. ACS Applied Materials and Interfaces, 9(40), 34970-34978
Open this publication in new window or tab >>Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells
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2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 40, p. 34970-34978Article in journal (Refereed) Published
Abstract [en]

Metal halide perovskites have emerged as materials of high interest for solar energy-to-electricity conversion, and in particular, the use of mixed-ion structures has led to high power conversion efficiencies and improved stability. For this reason, it is important to develop means to obtain atomic level understanding of the photoinduced behavior of these materials including processes such as photoinduced phase separation and ion migration. In this paper, we implement a new methodology combining visible laser illumination of a mixed-ion perovskite ((FAP-bI(3))(0.85)(MAPbBr(3))(0.15)) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
photoelectron spectroscopy, laser illumination, lead halide perovskite, ion migration, phase separation, stability
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-340141 (URN)10.1021/acsami.7b10643 (DOI)000413131500043 ()28925263 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 321319Swedish Research Council, 2014-6019Swedish Research Council, 2014-6463StandUpSwedish Foundation for Strategic Research , RMA15-0130
Available from: 2018-01-26 Created: 2018-01-26 Last updated: 2018-01-26Bibliographically approved
Patanen, M., Svensson, S. & Mårtensson, N. (2015). Electron spectroscopy using ultra brilliant synchrotron X-ray sources. Journal of Electron Spectroscopy and Related Phenomena, 200, 78-93
Open this publication in new window or tab >>Electron spectroscopy using ultra brilliant synchrotron X-ray sources
2015 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 200, p. 78-93Article in journal (Refereed) Published
Abstract [en]

The development of photoelectron spectroscopy since the early days of the technique is discussed. The focus is on the interaction between instrumental development and scientific achievements. In particular the opportunities provided by the increasingly brilliant synchrotron radiation sources are discussed. The contribution is focused on core level studies. The recent development is demonstrated by using selected examples obtained at today's most advanced synchrotron radiation facilities. The spectral resolution and intensity that can be reached at these facilities reveal new effects and provide detailed information on the investigated systems. The examples are mainly taken from studies of atoms and molecules where different effects can be most accurately identified and separated.

Keywords
Photoelectron spectroscopy, Synchrotron radiation, Broadening mechanisms
National Category
Physical Sciences
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-267078 (URN)10.1016/j.elspec.2015.04.011 (DOI)000362607600009 ()
Projects
UBjL
Funder
Swedish Research CouncilEU, European Research CouncilCarl Tryggers foundation
Available from: 2015-11-20 Created: 2015-11-17 Last updated: 2017-12-01Bibliographically approved
Gorgoi, M., Mårtensson, N. & Svensson, S. (2015). HAXPES studies of solid materials for applications in energy and information technology using the HIKE facility at HZB-BESSY II. Journal of Electron Spectroscopy and Related Phenomena, 200, 40-48
Open this publication in new window or tab >>HAXPES studies of solid materials for applications in energy and information technology using the HIKE facility at HZB-BESSY II
2015 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 200, p. 40-48Article in journal (Refereed) Published
Abstract [en]

In the present work we review a number of research directions addressed at the HIKE end-station at the BESSY II storage ring at the Helmholtz-Zentrum Berlin, HZB, using hard X-ray photoelectron spectroscopy (HAXPES). The emphasis of this review is on the specific properties of the technique, which are required in order to address different scientific questions at the HIKE beamline.

Place, publisher, year, edition, pages
Elsevier: , 2015
Keywords
Photoelectron spectroscopy, Hard X-ray photoelectron spectroscopy, HAXPES, HIKE, ESCA
National Category
Physical Sciences Natural Sciences
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-267077 (URN)10.1016/j.elspec.2015.05.005 (DOI)000362607600006 ()
Projects
UBjL
Funder
Swedish Research CouncilCarl Tryggers foundation EU, European Research Council
Available from: 2015-11-20 Created: 2015-11-17 Last updated: 2017-12-01Bibliographically approved
Mårtensson, N. & Svensson, S. (2015). New determination of the core-level life-time broadenings in mercury. Electronic Journal of Information Systems Evaluation, 202, 33-37
Open this publication in new window or tab >>New determination of the core-level life-time broadenings in mercury
2015 (English)In: Electronic Journal of Information Systems Evaluation, ISSN 1566-6379, E-ISSN 1566-6379, Vol. 202, p. 33-37Article in journal (Refereed) Published
Abstract [en]

Previously recorded and published photoelectron spectroscopic data for mercury in the gas phase has been reanalyzed. The life-time broadenings have been determined for a large number of core levels. It is then seen that a recent detailed derivation of core-level line-widths based on X-ray emission spectroscopy give life-time widths that are generally too large. The 4d(3/2)4d(5/2)nd Coster-Kronig (CM) transition is also discussed. We find that the additional broadening Of the 4d(3/2) level for mercury metal is indeed due to a CM decay, in contrast to recent claims. In atomic mercury, however, the CM process in energetically forbidden. In spite of this we find that the 4d(3/2) level is broadened also in this case. We propose that this is due to a mixing between the 4d(3/2) hole state and discrete 4d(5/2)nd states.

Place, publisher, year, edition, pages
Elsevier: , 2015
Keywords
Photoelectron spectroscopy, Core level, Life-time, Mercury
National Category
Physical Sciences
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-260639 (URN)10.1016/j.elspec.2015.01.002 (DOI)000357904600007 ()
Projects
UBjL
Funder
Swedish Research CouncilEU, European Research Council, 321319Carl Tryggers foundation
Available from: 2015-08-21 Created: 2015-08-21 Last updated: 2017-12-04Bibliographically approved
Mårtensson, N., Sokolowski, E. & Svensson, S. (2014). 50 years anniversary of the discovery of the core level chemical shifts. The early years of photoelectron spectroscopy. Journal of Electron Spectroscopy and Related Phenomena, 193, 27-33
Open this publication in new window or tab >>50 years anniversary of the discovery of the core level chemical shifts. The early years of photoelectron spectroscopy
2014 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 193, p. 27-33Article in journal (Refereed) Published
Abstract [en]

The pioneering years of photoelectron spectroscopy in Uppsala are discussed, especially the work leading to the discovery of the core level chemical shifts. At a very early stage of the project, the pioneering group observed what they described as evidence for chemical shifts in the core level binding energies. However, it can now be seen that the initial observations to a large extent was due to charging of the samples. It is interesting to note that the decisive experiment was realized, not as a result of a systematic study, but was obtained with a large element of serendipity. Only when a chemical binding energy shift was observed between two S2p electron lines in the same molecule, the results were accepted internationally, and the fascinating expansion of modern core level photoelectron spectroscopy could start.

Keywords
Electron, Spectroscopy, Pioneering, Years, Core, Level, Binding, Energy, Chemical, Shift
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-228515 (URN)10.1016/j.elspec.2014.02.005 (DOI)000337010200005 ()
Available from: 2014-07-16 Created: 2014-07-16 Last updated: 2017-12-05Bibliographically approved
Holldack, K., Ovsyannikov, R., Kuske, P., Mueller, R., Schaelicke, A., Scheer, M., . . . Foehlisch, A. (2014). Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source. Nature Communications, 5, Article ID 4010.
Open this publication in new window or tab >>Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source
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2014 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 5, article id 4010Article in journal (Refereed) Published
Abstract [en]

Synchrotron radiation facilities routinely operate in a multi-bunch regime, but applications relying on time-of-flight schemes require single bunch operation. Here we show that pulse picking by resonant excitation in a storage ring creates in addition to the multi-bunch operation a distinct and separable single bunch soft X-ray source. It has variable polarization, a photon flux of up to 10(7)-10(9) ph s(-1)/0.1%BW at purity values of 10(4)-10(2) and a repetition rate of 1.25 MHz. The quasi-resonant excitation of incoherent betatron oscillations of electrons allows horizontal pulse separation at variable (also circular) polarization accessible for both, regular 30 ps pulses and ultrashort pulses of 2-3 ps duration. Combined with a new generation of angularly resolving electron spectrometers this creates unique opportunities for time-resolved photoemission studies as confirmed by time-of-flight spectra. Our pulse picking scheme is particularly suited for surface physics at diffraction-limited light sources promising ultimate spectral resolution.

National Category
Condensed Matter Physics Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-228559 (URN)10.1038/ncomms5010 (DOI)000337542400002 ()
Projects
ESUX UBjL
Funder
Swedish Research CouncilEU, European Research CouncilCarl Tryggers foundation VINNOVA
Available from: 2014-07-17 Created: 2014-07-16 Last updated: 2017-12-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2978-1870

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