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Orzanowska G, Ryppa C, Senge MO, Waluk J. Fine-tuning of radiative properties by "mild" substituents: searching for a perfectly soft chromophore. Phys Chem Chem Phys 2024; 26:17944-17950. [PMID: 38888633 DOI: 10.1039/d4cp01502a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Controlling spectral properties to achieve desired characteristics is an attractive goal in application-oriented research, e.g., in the design of fluorescence sensors. "Soft" chromophores, molecules with strong spectral responses to internal or external perturbations are good candidates for such studies. In this work, absorption, fluorescence, and magnetic circular dichroism (MCD) spectra were obtained for a series of porphyrins, substituted at the meso-positions with n-hexyl groups. As the number of substituents increases from 1 to 4, significant changes are observed. The intensity of the S0-S1 transition (Qx) in the 0-0 region strongly decreases in mono-substituted porphyrin, but upon additional substitutions it increases to values larger than in the parent, unsubstituted molecule. Such behavior can be explained, using the perimeter model, by changes in the energy splittings between the two highest (HOMO) and two lowest (LUMO) frontier molecular orbitals. Single substitution makes porphyrin a nearly perfect soft chromophore, but upon introduction of a larger number of n-hexyl groups it is transformed into a hard one. DFT simulations incorrectly predict a continuous transition from a soft to hard chromophore, because the calculated ordering of two HOMO orbitals is opposite to that obtained by experiment. On the other hand, for those porphyrins that can be classified as hard chromophores, the calculations nicely reproduce contributions of Franck-Condon and Herzberg-Teller terms to absorption and fluorescence spectra.
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Affiliation(s)
- Grażyna Orzanowska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Claudia Ryppa
- School of Chemistry, Chair of Organic Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 52-160 Pearse Street, Dublin D02R590, Ireland
| | - Mathias O Senge
- School of Chemistry, Chair of Organic Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 52-160 Pearse Street, Dublin D02R590, Ireland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
- Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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2
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Waluk J. Nuclear Quantum Effects in Proton or Hydrogen Transfer. J Phys Chem Lett 2024; 15:598-607. [PMID: 38198616 PMCID: PMC10801683 DOI: 10.1021/acs.jpclett.3c03368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/12/2024]
Abstract
Proton or hydrogen transfers, basic chemical reactions, proceed either by thermally activated barrier crossing or via tunneling. Studies of molecules undergoing single or double proton or hydrogen transfer in the ground or excited electronic state reveal that tunneling can dominate under conditions usually considered to favor the thermal process. Moreover, the tunneling probability strongly varies for excitation of certain vibrational modes, which changes the effective barrier and/or proton transfer distance. When the reaction is fast compared to vibrational relaxation, the mode selectivity can still be maintained for molecules in solutions at 293 K. These observations point to dangers of relating the calculated minimum energy paths and the associated barriers to the experimentally obtained activation energies. The multidimensional character of the reaction coordinate is obvious; it can dramatically change for slowly and rapidly relaxing environments. We postulate that the hydrogen bond definition should be extended by specifically including the role of molecular vibrations.
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Affiliation(s)
- Jacek Waluk
- Institute
of Physical Chemistry, Polish Academy of
Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Faculty
of Mathematics and Science, Cardinal Stefan
Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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3
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Waluk J. Coupling between tautomerism and radiationless deactivation in porphycenes. PURE APPL CHEM 2023. [DOI: 10.1515/pac-2022-1107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Abstract
Quantum yields of fluorescence of porphycenes – porphyrin isomers – can vary by orders of magnitude, even for very similar derivatives, such as meso-dimethyl- vs. meso-tetramethylporphycene. In weakly emitting porphycenes the fluorescence intensity strongly depends on viscosity and can be recovered by placing a molecule in a rigid environment. We postulate that the efficient nonradiative deactivation is due to the quantum effect, delocalization of the inner protons. The delocalization, which increases with the strength of intramolecular hydrogen bonds may induce structural changes that lead to distortion from planarity and, as a result, efficient S0 ← S1 internal conversion. The effect seems to be general, as indicated by good correlation between the quantum yield of fluorescence and the distance between H-bonded nitrogen atoms, the latter being a reliable measure of hydrogen bonding strength. Based on the available photophysical and X-ray data, such correlation was found so far for over 20 differently substituted porphycenes.
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Affiliation(s)
- Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw , Poland
- Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University , Dewajtis 5, 01-815 Warsaw , Poland
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4
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Mbakara I, Gajewska A, Listkowski A, Kijak M, Nawara K, Kumpulainen T, Vauthey E, Waluk J. Spectroscopic investigation of photophysics and tautomerism of amino- and nitroporphycenes. Phys Chem Chem Phys 2022; 24:29655-29666. [PMID: 36453100 DOI: 10.1039/d2cp04555a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Parent, unsubstituted porphycene and its two derivatives: 2,7,12,17-tetra-n-propylporphycene and 2,7,12,17-tetra-t-butylporphycene were substituted at the meso position with amino and nitro groups. These two families of porphycenes were characterized in detail with respect to their spectral, photophysical, and tautomeric properties. Two trans tautomers of similar energies coexist in the ground electronic state, but only one form dominates in the lowest excited singlet state. Absorption, magnetic circular dichroism (MCD), and emission anisotropy combined with quantum-chemical calculations led to the assignment of S1 and S2 transitions in both tautomers. Compared with the parent porphycene, the S1-S2 energy gap significantly increases; for one tautomeric form, the effect is twice as large as for the other. Both amino- and nitroporphycenes emit single fluorescence; previously reported dual emission of aminoporphycenes is attributed to a degradation product. Introduction of bulky t-butyl groups leads to a huge decrease in fluorescence intensity; this effect, arising from the interaction of the meso substituent with the adjacent t-butyl moiety, is particularly strong in the nitro derivative.
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Affiliation(s)
- Idaresit Mbakara
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.
| | - Agnieszka Gajewska
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.
| | - Arkadiusz Listkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland. .,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
| | - Michał Kijak
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.
| | - Krzysztof Nawara
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland. .,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
| | - Tatu Kumpulainen
- Physical Chemistry Department, Sciences II, University of Geneva, 30, Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Eric Vauthey
- Physical Chemistry Department, Sciences II, University of Geneva, 30, Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland. .,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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5
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Pszona M, Gawinkowski S, Jäger R, Kamińska I, Waluk J. Influence of bulky substituents on single-molecule SERS sensitivity. J Chem Phys 2022; 156:014201. [PMID: 34998322 DOI: 10.1063/5.0074840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The surface-enhanced Raman spectroscopy (SERS) detection limit strongly depends on the molecular structure, which we demonstrate for a family of tert-butyl-substituted porphycenes. Even though the investigated species present very similar photophysical properties, the ratio between the SERS signal and fluorescence background depends on the number of bulky tert-butyl groups. Moreover, the probability of single molecule detection systematically drops with the number of the moieties attached to the pyrrole ring. As steric hindrance is the only significantly changing feature among the studied chromophores, we attribute the observed phenomena to the spatial structure. We also show that the sensitivity of the SERS technique can be improved by lowering the temperature. We managed to observe single-molecule spectra for derivatives for which this was unattainable at room temperature.
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Affiliation(s)
- Maria Pszona
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Sylwester Gawinkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Regina Jäger
- Institute of Physical and Theoretical Chemistry and LISA, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
| | - Izabela Kamińska
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
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Koga D, Ono T, Shinjo H, Hisaeda Y. Hydrogen Bond Engineering Visualized by Picometer-Level Distortion of Planar Porphyrin Isomers. J Phys Chem Lett 2021; 12:10429-10436. [PMID: 34672583 DOI: 10.1021/acs.jpclett.1c03020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Directly investigating hydrogen bond (HB) dynamics in molecular materials is a challenging task. Here, we report a set of porphyrin isomers, porphycenes, that visualize slight changes on the order of picometers in the intramolecular HB dynamics. Intramolecular HBs of porphycenes were regulated by the systematic modification at meso positions with methyl (Me), cyclopentyl (Cy5), and cyclohexyl (Cy6) moieties. Notably, the quantum yields varied from 35 to 0.04% in chloroform, depending on a slight distortion in the porphycene framework. SC-XRD, XPS, and NMR clearly revealed that the Me and Cy6 moieties increased the nonradiative deactivation by strengthening the intramolecular NH···N HBs whereas Cy5 retained their photoluminescence properties. This is the first example of how the distortion of planar porphyrinoids at the picometer level along with the strength of the intramolecular NH···N HBs can drastically affect their optical properties. The results revealed new avenues of HB engineering based on porphyrinoids.
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7
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Kelm A, Ostapko J, Gajewska A, Sánchez-Iglesias A, Waluk J. Spectral and photophysical modifications of porphyrins attached to core-shell nanoparticles. Theory and experiment. Methods Appl Fluoresc 2021; 9. [PMID: 34256360 DOI: 10.1088/2050-6120/ac1400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/13/2021] [Indexed: 12/30/2022]
Abstract
Plasmonic nanostructures, of which gold nanoparticles are the most elementary example, owe their unique properties to localized surface plasmons (LSP), the modes of free electron oscillation. LSP alter significantly electromagnetic field in the nanostructure neighborhood (i.e., near-field), which can modify the electric dipole transition rates in organic emitters. This study aims at investigating the influence of Au@SiO2core-shell nanoparticles on the photophysics of porphyrins covalently attached to the nanoparticles surface. Guided by theoretical predictions, three sets of gold nanoparticles of different sizes were coated with a silica layer of similar thickness. The outer silica surface was functionalized with either free-basemeso-tetraphenylporphyrin or its zinc complex. Absorption and emission bands of porphyrin overlap in energy with a gold nanoparticle LSP resonance that provides the field enhancement. Silica separates the emitters from the gold surface, while the gold core size tunes the energy of the LSP resonance. The signatures of weak-coupling regime have been observed. Apart from modified emission profiles and shortened S1lifetimes, Q band part intensity of the excitation spectra significantly increased with respect to the Soret band. The results were explained using classical transfer matrix simulations and electronic states kinetics, taking into account the photophysical properties of each chromophore. The calculations could reasonably well predict and explain the experimental outcomes. The discrepancies between the two were discussed.
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Affiliation(s)
- A Kelm
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - J Ostapko
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - A Gajewska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - A Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain.,Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain
| | - J Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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8
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Bednarz A, Kamińska I, Jamrozik A, Zielonka K, Listkowski A, Waluk J. Substituent screening effect on single-molecule photostability: comparison of three differently substituted porphycenes. Methods Appl Fluoresc 2021; 9. [PMID: 33910172 DOI: 10.1088/2050-6120/abfcac] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/28/2021] [Indexed: 11/12/2022]
Abstract
Photobleaching of single molecules has been studied using confocal fluorescence microscopy for porphycene, a porphyrin isomer, and its two derivatives. Fourfold substitution of porphycene with bulkytert-butyl groups leads to the enhancement of photostability, even though the spectral, photophysical, and redox parameters remain similar. We attribute this effect to the increase of the efficiency of physical quenching of the chromophore triplet state by oxygen, compared with the yield of chemical reaction that leads to photobleaching. Analysis of the observed photon fluxes from single emitters embedded in a polymer film shows that the experiment based on fluorescence is biased towards detection of molecules which have oxygen-the triplet quencher-in their vicinity. The distribution of the measured photodegradation quantum yields is very heterogeneous, suggesting that physical and chemical quenching rates exhibit different distance and orientation dependences.
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Affiliation(s)
- Aleksandra Bednarz
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Izabela Kamińska
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Agnieszka Jamrozik
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Karolina Zielonka
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland
| | - Arkadiusz Listkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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9
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Listkowski A, Masiera N, Kijak M, Luboradzki R, Leśniewska B, Waluk J. Controlling Emissive Properties by Intramolecular Hydrogen Bonds: Alkyl and Aryl meso-Substituted Porphycenes. Chemistry 2021; 27:6324-6333. [PMID: 33561303 DOI: 10.1002/chem.202005440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Indexed: 01/09/2023]
Abstract
Porphycene, a porphyrin isomer, is an efficient fluorophore. However, four-fold meso substitution with alkyl groups decreases the fluorescence quantum yield by orders of magnitude. For aryl substituents, this effect is small. To explain this difference, we have synthesized and studied a mixed aryl-alkyl-substituted compound, 9,20-diphenyl-10,19-dimethylporphycene, as well as the 9,20-diphenyl and 9,20-dimethyl derivatives. Analysis of the structural, spectroscopic, and photophysical data of the six porphycenes, combined with quantum chemical calculations, shows a clear correlation between the strength of the intramolecular NH⋅⋅⋅N hydrogen bonds and the efficiency of the radiationless depopulation of the lowest-excited singlet state. This result led us to propose a model in which the delocalization of the inner protons in the cavity of the macrocycle is responsible for the nonradiative deactivation channel. The applicability of the model is confirmed by the literature data for other alkyl- or aryl-substituted porphycenes. The finding of a correlation between structural and emissive characteristics enables a rational design of porphycenes with desired photophysical properties.
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Affiliation(s)
- Arkadiusz Listkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815, Warsaw, Poland
| | - Natalia Masiera
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Michał Kijak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Roman Luboradzki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Barbara Leśniewska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815, Warsaw, Poland
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Listkowski A, Kharchenko A, Ciąćka P, Kijak M, Masiera N, Rybakiewicz R, Luboradzki R, Fita P, Waluk J. Fluorinated Porphycenes: Synthesis, Spectroscopy, Photophysics, and Tautomerism. Chempluschem 2020; 85:2197-2206. [DOI: 10.1002/cplu.202000517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/08/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Arkadiusz Listkowski
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
- Faculty of Mathematics and Natural Sciences College of Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
| | - Anastasiia Kharchenko
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
| | - Piotr Ciąćka
- Institute of Experimental Physics Faculty of Physics University of Warsaw Pasteura 5 02-093 Warsaw Poland
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
| | - Michał Kijak
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
| | - Natalia Masiera
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
| | - Renata Rybakiewicz
- Faculty of Mathematics and Natural Sciences College of Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
| | - Roman Luboradzki
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
| | - Piotr Fita
- Institute of Experimental Physics Faculty of Physics University of Warsaw Pasteura 5 02-093 Warsaw Poland
| | - Jacek Waluk
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44 01-224 Warsaw Poland
- Faculty of Mathematics and Natural Sciences College of Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
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