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Hemmeter D, Kremitzl D, Schulz PS, Wasserscheid P, Maier F, Steinrück HP. The Buoy Effect: Surface Enrichment of a Pt Complex in IL Solution by Ligand Design. Chemistry 2023; 29:e202203325. [PMID: 36446030 PMCID: PMC10107114 DOI: 10.1002/chem.202203325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 11/30/2022]
Abstract
The targeted enrichment of a Pt complex with an ionic liquid (IL)-derived ligand system in IL solution is demonstrated by using angle-resolved X-ray photoelectron spectroscopy. When the ligand system is complemented with fluorinated side chains, the complex accumulates strongly at the IL/gas interface, while in an equivalent solution of a complex without these substituents no such effect could be observed. This buoy-like behavior induces strong population of the complex at the outermost molecular layer close to surface saturation, which was studied over a range from 5 to 30 %mol . The surface enrichment was found to be most efficient at the lowest concentration, which is particularly favorable for catalytic applications such as supported ionic-liquid-phase (SILP) catalysis.
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Affiliation(s)
- Daniel Hemmeter
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Daniel Kremitzl
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Peter S Schulz
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Peter Wasserscheid
- Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.,Forschungszentrum Jülich GmbH, Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Egerlandstr. 3, 91058, Erlangen, Germany
| | - Florian Maier
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
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2
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Seymour JM, Gousseva E, Large AI, Clarke CJ, Licence P, Fogarty RM, Duncan DA, Ferrer P, Venturini F, Bennett RA, Palgrave RG, Lovelock KRJ. Experimental measurement and prediction of ionic liquid ionisation energies. Phys Chem Chem Phys 2021; 23:20957-20973. [PMID: 34545382 DOI: 10.1039/d1cp02441h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquid (IL) valence electronic structure provides key descriptors for understanding and predicting IL properties. The ionisation energies of 60 ILs are measured and the most readily ionised valence state of each IL (the highest occupied molecular orbital, HOMO) is identified using a combination of X-ray photoelectron spectroscopy (XPS) and synchrotron resonant XPS. A structurally diverse range of cations and anions were studied. The cation gave rise to the HOMO for nine of the 60 ILs presented here, meaning it is energetically more favourable to remove an electron from the cation than the anion. The influence of the cation on the anion electronic structure (and vice versa) were established; the electrostatic effects are well understood and demonstrated to be consistently predictable. We used this knowledge to make predictions of both ionisation energy and HOMO identity for a further 516 ILs, providing a very valuable dataset for benchmarking electronic structure calculations and enabling the development of models linking experimental valence electronic structure descriptors to other IL properties, e.g. electrochemical stability. Furthermore, we provide design rules for the prediction of the electronic structure of ILs.
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Affiliation(s)
- Jake M Seymour
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
| | | | - Alexander I Large
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK. .,Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | - Coby J Clarke
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter Licence
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | | | - Pilar Ferrer
- Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | | | - Roger A Bennett
- Department of Chemistry, University of Reading, Reading, RG6 6AD, UK.
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3
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Nemoto F, Nakamura SY, Abe H. Surface structure of the mixture of 1-alkyl-3-methylimidazolium iodide and polyiodide observed by surface tension measurement and X-ray reflectivity. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Kuusik I, Kook M, Pärna R, Kisand V. Ionic Liquid Vapors in Vacuum: Possibility to Derive Anodic Stabilities from DFT and UPS. ACS OMEGA 2021; 6:5255-5265. [PMID: 33681566 PMCID: PMC7931180 DOI: 10.1021/acsomega.0c05369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/29/2021] [Indexed: 05/28/2023]
Abstract
Ultraviolet photoelectron spectroscopy (UPS) investigations of several gas-phase ionic liquid (IL) ion pairs have been conducted. [EMIM][OTF], [PYR14][OTF], [EMIM][DCA], [PYR14][DCA], [PYR14][TCM], [PYR14][FSI], [PYR14][PF6], [S222][TFSI], [P4441][TFSI], and [EMMIM][TFSI] vapor UPS spectra are presented for the first time. The experimental low-binding-energy cutoff value (highest occupied molecular orbital, HOMO energy) of the ionic liquid ion pairs, which is of great interest, has been measured. Many studies use calculated gas-phase electronic properties to estimate the liquid-phase electrochemical stability. Hybrid density functional theory (DFT) calculations have been used to interpret the experimental data. The gas-phase photoelectron spectra in conjunction with the theoretical calculations are able to verify most HOMO energies and assign them to the cation or anion. The hybrid M06 functional is shown to offer a very good description of the ionic liquid electronic structure. In some cases, the excellent agreement between the UPS spectra and the M06 calculation validates the conformer found and constitutes as a first indirect experimental determination of ionic liquid ion-pair structure. Comparisons with recent theoretical studies are made, and implications for electrochemical applications are discussed. The new data provide a much-needed reference for future ab initio calculations and support the argument that modeling of IL cations and anions separately is incorrect.
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Affiliation(s)
- Ivar Kuusik
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Mati Kook
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Rainer Pärna
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Vambola Kisand
- Institute of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
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5
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Rangan S, Viereck J, Bartynski RA. Electronic Properties of Cyano Ionic Liquids: a Valence Band Photoemission Study. J Phys Chem B 2020; 124:7909-7917. [DOI: 10.1021/acs.jpcb.0c06423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sylvie Rangan
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Jonathan Viereck
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Robert A. Bartynski
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
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Hemming EB, Masters AF, Maschmeyer T. Immobilisation of Homogeneous Pd Catalysts within a Type I Porous Liquid. Aust J Chem 2020. [DOI: 10.1071/ch20256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An N-heterocyclic carbene-based palladium complex was successfully immobilised on the inner surfaces of hollow silica nanospheres. The external surfaces of these spheres were functionalised with a corona-canopy to produce a Type I porous liquid. To confirm the successful immobilisation of the catalytic precursor, the porous liquid system was explored using the Heck reaction as a model reaction. This work demonstrated that homogeneous catalysts can be successfully immobilised within porous liquids in principle and that the approach used could be readily adapted for the immobilisation of other systems.
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Kuusik I, Kook M, Pärna R, Kivimäki A, Käämbre T, Reisberg L, Kikas A, Kisand V. The electronic structure of ionic liquids based on the TFSI anion: A gas phase UPS and DFT study. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Fogarty RM, Palgrave RG, Bourne RA, Handrup K, Villar-Garcia IJ, Payne DJ, Hunt PA, Lovelock KRJ. Electron spectroscopy of ionic liquids: experimental identification of atomic orbital contributions to valence electronic structure. Phys Chem Chem Phys 2019; 21:18893-18910. [PMID: 31441923 DOI: 10.1039/c9cp02200g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The atomic contributions to valence electronic structure for 37 ionic liquids (ILs) are identified using a combination of variable photon energy XPS, resonant Auger electron spectroscopy (RAES) and a subtraction method. The ILs studied include a diverse range of cationic and anionic structural moieties. We introduce a new parameter for ILs, the energy difference between the energies of the cationic and anionic highest occupied fragment orbitals (HOFOs), which we use to identify the highest occupied molecular orbital (HOMO). The anion gave rise to the HOMO for 25 of the 37 ILs studied here. For 10 of the ILs, the energies of the cationic and anionic HOFOs were the same (within experimental error); therefore, it could not be determined whether the HOMO was from the cation or the anion. For two of the ILs, the HOMO was from the cation and not from the anion; consequently it is energetically more favourable to remove an electron from the cation than the anion for these two ILs. In addition, we used a combination of area normalisation and subtraction of XP spectra to produce what are effectively XP spectra for individual ions; this was achieved for 10 cations and 14 anions.
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Affiliation(s)
| | | | - Richard A Bourne
- Institute of Process Research and Development, Schools of Chemistry and Chemical and Process Engineering, University of Leeds, UK
| | | | | | - David J Payne
- Department of Materials, Imperial College London, UK
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Kuusik I, Berholts M, Kruusma J, Tõnisoo A, Lust E, Nõmmiste E, Kisand V. Valence electronic structure of [EMIM][B(CN)4]: ion-pair vs. bulk description. RSC Adv 2019; 9:33140-33146. [PMID: 35529163 PMCID: PMC9073151 DOI: 10.1039/c9ra06762k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/10/2019] [Indexed: 11/21/2022] Open
Abstract
The ultraviolet photoelectron spectrum of the [EMIM][B(CN)4] ionic liquid was recorded and analyzed. Together with different ab initio calculation methods, detailed insight into the electronic structure of this simple room temperature ionic liquid is possible. The ion-pair approximation to the liquid electronic structure was not sufficient. Therefore bulk ab initio calculations were performed on a proposed crystal structure. The modelling of bulk electronic spectra is able to explain the experimental electronic structure of the ionic liquid. Most notably, the dispersion corrected PBE calculation (PBE-D3BJ) showed good agreement with the experimental UPS spectrum. The spectra simulated by the B97-D and the BLYP-D3(BJ) functionals were also in agreement with the experimental data. The LDA approximation only provided qualitative agreement while the optB88-vdW and CX-vdW functionals were not good. However, it will be shown that many requirements have to be met in order to accurately describe the electronic structure of this ionic liquid. The ultraviolet photoelectron spectrum of the [EMIM][B(CN)4] ionic liquid was recorded and simulated using different ab initio ion-pair and bulk calculation methods.![]()
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Affiliation(s)
- I. Kuusik
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - M. Berholts
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
- Dept. of Physics and Astronomy
| | - J. Kruusma
- Institute of Chemistry
- University of Tartu
- 50411 Tartu
- Estonia
| | - A. Tõnisoo
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - E. Lust
- Institute of Chemistry
- University of Tartu
- 50411 Tartu
- Estonia
| | - E. Nõmmiste
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - V. Kisand
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
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Kuusik I, Berholts M, Kruusma J, Kisand V, Tõnisoo A, Lust E, Nõmmiste E. Valence electronic structure of [EMIM][BF4] ionic liquid: photoemission and DFT+D study. RSC Adv 2018; 8:30298-30304. [PMID: 35546846 PMCID: PMC9085424 DOI: 10.1039/c8ra05865b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 08/22/2018] [Indexed: 11/21/2022] Open
Abstract
The ultraviolet photoelectron spectrum (UPS) of the [EMIM][BF4] ionic liquid was recorded and analyzed. Together with the gas-phase UPS spectrum of the [EMIM][BF4] vapor and ab initio calculation methods, detailed insight into the electronic structure of this simple ionic liquid is possible. The low binding energy tail in the UPS spectrum is about 7.4 eV, in agreement with previous estimations of the HOMO–LUMO gap of the [EMIM][BF4] ion-pair. The bulk ab initio calculations are able to explain most of the features in the spectrum. However, DFT consistently lacks accuracy in the description of the top of the valence band. The dispersion corrected PBE calculation (PBE-D3) did offer very good agreement with the experimental structure, but the recently-developed vdW-DF functionals C09, optPBE, optB88 and CX were found to offer the best agreement in terms of the electronic structure. The ultraviolet photoelectron spectrum (UPS) of the [EMIM][BF4] ionic liquid was recorded and compared to previously measured vapor phase UPS spectrum.![]()
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Affiliation(s)
- I. Kuusik
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - M. Berholts
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
- Dept. of Physics and Astronomy
| | - J. Kruusma
- Institute of Chemistry
- University of Tartu
- 50411 Tartu
- Estonia
| | - V. Kisand
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - A. Tõnisoo
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
| | - E. Lust
- Institute of Chemistry
- University of Tartu
- 50411 Tartu
- Estonia
| | - E. Nõmmiste
- Institute of Physics
- University of Tartu
- 50411 Tartu
- Estonia
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Biedron AB, Garfunkel EL, Castner EW, Rangan S. Ionic liquid ultrathin films at the surface of Cu(100) and Au(111). J Chem Phys 2017; 146:054704. [DOI: 10.1063/1.4975101] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Aleksandra B. Biedron
- Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Eric L. Garfunkel
- Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Edward W. Castner
- Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA
| | - Sylvie Rangan
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
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12
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Surface composition of [BMP][Tf2N] and [PMIm][Tf2N] in the presence of NbF5 and TaF5. A photoelectron spectroscopy study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.08.075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Kuusik I, Tarkanovskaja M, Kruusma J, Kisand V, Tõnisoo A, Lust E, Nõmmiste E. Valence band photoelectron spectra of [EMIM][BF 4 ] ionic liquid vapor: Evidences of electronic relaxation. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.08.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Seo S, Park J, Kang YC. Chemical Analysis of Ionic Liquids Using Photoelectron Spectroscopy. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- SungYong Seo
- Department of Chemistry; Pukyong National University; Busan 608-737 Republic of Korea
| | - Juyun Park
- Department of Chemistry; Pukyong National University; Busan 608-737 Republic of Korea
| | - Yong-Cheol Kang
- Department of Chemistry; Pukyong National University; Busan 608-737 Republic of Korea
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Borgwardt M, Wilke M, Kiyan IY, Aziz EF. Ultrafast excited states dynamics of [Ru(bpy)3]2+ dissolved in ionic liquids. Phys Chem Chem Phys 2016; 18:28893-28900. [DOI: 10.1039/c6cp05655e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In this work, we demonstrate the potential of room-temperature ionic liquids as solvents to investigate the excited states dynamics of [Ru(bpy)3]2+ by means of time-resolved photoelectron spectroscopy.
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Affiliation(s)
- Mario Borgwardt
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Martin Wilke
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Igor Yu. Kiyan
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Emad F. Aziz
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
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