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Publications (10 of 68) Show all publications
Poline, M., Dochain, A., Rosén, S., Ji, M., Reinhed, P., Simonsson, A., . . . Viggiano, A. A. (2024). Mutual Neutralization of NO plus with O-. Physical Review Letters, 132(2), Article ID 023001.
Open this publication in new window or tab >>Mutual Neutralization of NO plus with O-
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2024 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 132, no 2, article id 023001Article, review/survey (Refereed) Published
Abstract [en]

We have studied the mutual neutralization reaction of vibronically cold NO+ with O- at a collision energy of approximate to 0.1 eV and under single-collision conditions. The reaction is completely dominated by production of three ground-state atomic fragments. We employ product-momentum analysis in the framework of a simple model, which assumes the anion acts only as an electron donor and the product neutral molecule acts as a free rotor, to conclude that the process occurs in a two-step mechanism via an intermediate Rydberg state of NO which subsequently fragments.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-228987 (URN)10.1103/PhysRevLett.132.023001 (DOI)001185794500009 ()38277613 (PubMedID)2-s2.0-85182266242 (Scopus ID)
Available from: 2024-05-08 Created: 2024-05-08 Last updated: 2024-05-08Bibliographically approved
Nastasiienko, N., Kulik, T., Palianytsia, B., Larsson, M. & Kartel, M. (2023). Microwave-assisted catalytic pyrolysis of ferulic acid, as a lignin model compound. Journal of thermal analysis and calorimetry (Print), 148(12), 5485-5492
Open this publication in new window or tab >>Microwave-assisted catalytic pyrolysis of ferulic acid, as a lignin model compound
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2023 (English)In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 148, no 12, p. 5485-5492Article in journal (Refereed) Published
Abstract [en]

Studies of the effect of microwave (MW) pretreatment on the pyrolysis of ferulic acid (FA), as a model compound of lignin, on the CeO2 surface are essential for understanding the prospects for the use of MW in catalytic pyrolytic technologies for the processing of lignocellulose. In this work, FT-IR spectroscopic studies of MW-pretreated samples of FA on the nanoceria surface were carried out. Their pyrolysis was studied by temperature-programmed desorption mass spectrometry (TPD MS). It was found that monodentate carboxylate complexes of FA are most susceptible to the influence of MW. MW-pretreatment for 300 s during pyrolysis of FA on the CeO2 surface leads to a decrease in the content of 4-vinylguaiacol in the final pyrolysis products. Phenolate complexes, as well as bidentate carboxylate complexes of FA on the CeO2 surface are less sensitive to MW. The use of MW-pretreatment promotes an insignificant decrease in the formation of polyaromatic compounds during the FA catalytic pyrolysis. 

Keywords
Surface complexes, Cerium oxide, Microwave pretreatment, FT-IR spectroscopy, Thermal transformations, Temperature-programmed desorption mass spectrometry
National Category
Inorganic Chemistry Chemical Process Engineering
Identifiers
urn:nbn:se:su:diva-220561 (URN)10.1007/s10973-023-12087-3 (DOI)000983785500001 ()2-s2.0-85152033937 (Scopus ID)
Available from: 2023-09-04 Created: 2023-09-04 Last updated: 2023-09-04Bibliographically approved
Allum, F., Music, V., Inhester, L., Boll, R., Erk, B., Schmidt, P., . . . Ilchen, M. (2022). A localized view on molecular dissociation via electron-ion partial covariance. Communications Chemistry, 5(1), Article ID 42.
Open this publication in new window or tab >>A localized view on molecular dissociation via electron-ion partial covariance
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2022 (English)In: Communications Chemistry, E-ISSN 2399-3669, Vol. 5, no 1, article id 42Article in journal (Refereed) Published
Abstract [en]

Inner-shell photoelectron spectroscopy provides an element-specific probe of molecular structure, as core-electron binding energies are sensitive to the chemical environment. Short-wavelength femtosecond light sources, such as Free-Electron Lasers (FELs), even enable time-resolved site-specific investigations of molecular photochemistry. Here, we study the ultraviolet photodissociation of the prototypical chiral molecule 1-iodo-2-methylbutane, probed by extreme-ultraviolet (XUV) pulses from the Free-electron LASer in Hamburg (FLASH) through the ultrafast evolution of the iodine 4d binding energy. Methodologically, we employ electron-ion partial covariance imaging as a technique to isolate otherwise elusive features in a two-dimensional photoelectron spectrum arising from different photofragmentation pathways. The experimental and theoretical results for the time-resolved electron spectra of the 4d3/2 and 4d5/2 atomic and molecular levels that are disentangled by this method provide a key step towards studying structural and chemical changes from a specific spectator site.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-204058 (URN)10.1038/s42004-022-00656-w (DOI)000773922700001 ()
Available from: 2022-04-19 Created: 2022-04-19 Last updated: 2022-04-19Bibliographically approved
Poline, M., Rosén, S., Ji, M., Simonsson, A., Reinhed, P., Larsson, M., . . . Viggiano, A. A. (2022). Storage-ring study of the mutual neutralization of N+ with O−. Physical Review A: covering atomic, molecular, and optical physics and quantum information, 105(6), Article ID 062825.
Open this publication in new window or tab >>Storage-ring study of the mutual neutralization of N+ with O
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2022 (English)In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 105, no 6, article id 062825Article in journal (Refereed) Published
Abstract [en]

The double ion storage ring DESIREE has been used in combination with position- and time-sensitive detectors to study the mutual neutralization of N+ with O at 40 meV collision energy. Several previously unassigned spectral features observed in a recent single-pass merged-beams experiment at 7 meV collision energy [Phys. Rev. Lett. 121, 083401 (2018)], were also observed in the present experiment. It was found that neutralization channels of the first metastable state of the cation [N+(1D),τ≈256s] could explain the majority of these features, while the second metastable state [N+(1S),τ≈0.9s] was not found to contribute significantly. The branching ratios into the different electronically excited states of N were determined and found to be in good agreement between the two experiments. Theoretical calculations using the multichannel Landau-Zener model were found to yield good results for a number of channels, but could not describe some observed contributions, possibly due to the presence of other processes not accounted for in the model.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-211322 (URN)10.1103/physreva.105.062825 (DOI)000829758500002 ()2-s2.0-85133320356 (Scopus ID)
Funder
Swedish Research Council, 2020-05467Swedish Research Council, 2018-04092,Swedish Research Council, 2020-03404
Available from: 2022-11-17 Created: 2022-11-17 Last updated: 2022-11-23Bibliographically approved
Kulik, T., Nastasiienko, N., Palianytsia, B., Ilchenko, M. & Larsson, M. (2021). Catalytic Pyrolysis of Lignin Model Compound (Ferulic Acid) over Alumina: Surface Complexes, Kinetics, and Mechanisms. Catalysts, 11(12), Article ID 1508.
Open this publication in new window or tab >>Catalytic Pyrolysis of Lignin Model Compound (Ferulic Acid) over Alumina: Surface Complexes, Kinetics, and Mechanisms
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2021 (English)In: Catalysts, E-ISSN 2073-4344, Vol. 11, no 12, article id 1508Article in journal (Refereed) Published
Abstract [en]

Studies of the thermochemical properties of the important model compound of lignin-ferulic acid (FA) and its surface complexes are substantial for developing technologies for catalytic pyrolysis of renewable biomass into biofuels and lignin-derived chemicals as well as for bio-oil upgrading. In this work, the catalytic pyrolysis of ferulic acid over alumina was studied by temperature-programmed desorption mass spectrometry (TPD MS), in situ FT-IR spectroscopy, thermogravimetric analysis, and DFT calculations. We established that both the carboxyl group and the active groups (HO and CH3O) of the aromatic ring interact with the alumina surface. We calculated the kinetic parameters of formation of the main products of catalytic pyrolysis: 4-vinylguaiacol, guaiacol, hydroxybenzene, benzene, toluene, cresol, naphthalene, and PACs. Possible methods of their forming from the related surface complexes of FA are suggested.

Keywords
4-vinylguaiacol, guaiacol, benzene, hydroxybenzene, PACs, thermal transformations, FT-IR spectroscopy, TPD MS, pre-reaction complexes, DFT calculation, regeneration
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-201075 (URN)10.3390/catal11121508 (DOI)000736192100001 ()
Available from: 2022-01-18 Created: 2022-01-18 Last updated: 2022-01-18Bibliographically approved
Nastasiienko, N., Kulik, T., Palianytsia, B., Laskin, J., Cherniavska, T., Kartel, M. & Larsson, M. (2021). Catalytic Pyrolysis of Lignin Model Compounds (Pyrocatechol, Guaiacol, Vanillic and Ferulic Acids) over Nanoceria Catalyst for Biomass Conversion. Applied Sciences, 11(16), Article ID 7205.
Open this publication in new window or tab >>Catalytic Pyrolysis of Lignin Model Compounds (Pyrocatechol, Guaiacol, Vanillic and Ferulic Acids) over Nanoceria Catalyst for Biomass Conversion
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2021 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 11, no 16, article id 7205Article in journal (Refereed) Published
Abstract [en]

Understanding the mechanisms of thermal transformations of model lignin compounds (MLC) over nanoscale catalysts is important for improving the technologic processes occurring in the pyrolytic conversion of lignocellulose biomass into biofuels and value-added chemicals. Herein, we investigate catalytic pyrolysis of MLC (pyrocatechol (P), guaiacol (G), ferulic (FA), and vanillic acids (VA)) over nanoceria using FT-IR spectroscopy, temperature-programmed desorption mass spectrometry (TPD MS), and thermogravimetric analysis (DTG/DTA/TG). FT-IR spectroscopic studies indicate that the active groups of aromatic rings of P, G, VA, and FA as well as carboxylate groups of VA and FA are involved in the interaction with nanoceria surface. We explore the general transformation mechanisms of different surface complexes and identify their decomposition products. We demonstrate that decomposition of carboxylate acid complexes occurs by decarboxylation. When FA is used as a precursor, this reaction generates 4-vinylguaiacol. Complexes of VA and FA formed through both active groups of the aromatic ring and decompose on the CeO2 surface to generate hydroxybenzene. The formation of alkylated products accompanies catalytic pyrolysis of acids due to processes of transalkylation on the surface.

Keywords
kinetics and mechanisms, bio-oil upgrading, kinetic parameters, 4-vinylguaiacol, surface complex, FT-IR spectroscopy, temperature-programmed desorption mass spectrometry
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-197510 (URN)10.3390/app11167205 (DOI)000688711800001 ()
Available from: 2021-10-05 Created: 2021-10-05 Last updated: 2022-02-25Bibliographically approved
Nastasiienko, N., Kulik, T., Palianytsia, B., Larsson, M., Cherniavska, T. & Kartel, M. (2021). Decarboxylation of p-Coumaric Acid during Pyrolysis on the Nanoceria Surface. Colloids and Interfaces, 5(4), Article ID 48.
Open this publication in new window or tab >>Decarboxylation of p-Coumaric Acid during Pyrolysis on the Nanoceria Surface
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2021 (English)In: Colloids and Interfaces, ISSN 2504-5377, Vol. 5, no 4, article id 48Article in journal (Refereed) Published
Abstract [en]

Temperature-programmed desorption mass spectrometry (TPD MS) was used to study the pyrolysis of p-coumaric acid (pCmA) on the nanoceria surface. The interaction of pCmA with the CeO2 surface was investigated by FT-IR spectroscopy. The obtained data indicated the formation on the nanoceria surface of bidentate carboxylate complexes with chelate (Δν = 62 cm−1) and bridge structure (Δν = 146 cm−1). The thermal decomposition of pCmA over nanoceria occurred in several stages, mainly by decarboxylation. The main decomposition product is 4-vinylphenol (m/z 120). The obtained data can be useful for studying the mechanisms of catalytic thermal transformations of lignin-containing raw materials using catalysts containing cerium oxide and the development of effective technologies for the isolation of pCmA from lignin

Keywords
temperature-programmed desorption mass spectrometry, FT-IR spectroscopy, 4-vinyl phenol, lignin, biomass conversion
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-201302 (URN)10.3390/colloids5040048 (DOI)000736432100001 ()
Available from: 2022-01-24 Created: 2022-01-24 Last updated: 2022-01-24Bibliographically approved
Poline, M., Dochain, A., Rosén, S., Grumer, J., Ji, M., Eklund, G., . . . Thomas, R. D. (2021). Mutual neutralisation of O+ with O−: investigation of the role of metastable ions in a combined experimental and theoretical study. Physical Chemistry, Chemical Physics - PCCP, 23(43), 24607-24616
Open this publication in new window or tab >>Mutual neutralisation of O+ with O: investigation of the role of metastable ions in a combined experimental and theoretical study
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2021 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 23, no 43, p. 24607-24616Article in journal (Refereed) Published
Abstract [en]

The mutual neutralisation of O+ with O− has been studied in a double ion-beam storage ring with combined merged-beams, imaging and timing techniques. Branching ratios were measured at the collision energies of 55, 75 and 170 (± 15) meV, and found to be in good agreement with previous single-pass merged-beams experimental results at 7 meV collision energy. Several previously unidentified spectral features were found to correspond to mutual neutralisation channels of the first metastable state of the cation (O+(2Do), τ ≈ 3.6 hours), while no contributions from the second metastable state (O+(2Po), τ ≈ 5 seconds) were observed. Theoretical calculations were performed using the multi-channel Landau–Zener model combined with the anion centered asymptotic method, and gave good agreement with several experimentally observed channels, but could not describe well observed contributions from the O+(2Do) metastable state as well as channels involving the O(3s 5So) state.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-211321 (URN)10.1039/d1cp03977f (DOI)
Funder
Knut and Alice Wallenberg Foundation, 2018.0028Swedish Research Council, 2017-00621Swedish Research Council, 2018-04092Swedish Research Council, 2019-04379Swedish Research Council, 2020-03404Swedish Research Council, 2020-03437
Available from: 2022-11-17 Created: 2022-11-17 Last updated: 2023-10-13Bibliographically approved
Bohm, C., Danared, H., Hedqvist, A., Hellberg, F., Hidvégi, A., Larsson, M. & Robson, C. (2020). A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator. Nature Photonics, 14(6), 391-397
Open this publication in new window or tab >>A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator
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2020 (English)In: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 14, no 6, p. 391-397Article in journal (Refereed) Published
Abstract [en]

The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created. The first operation of the European X-ray free-electron laser facility accelerator based on superconducting technology is reported. The maximum electron energy is 17.5 GeV. A laser average power of 6 W is achieved at a photon energy of 9.3 keV.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-182975 (URN)10.1038/s41566-020-0607-z (DOI)000534781300003 ()2-s2.0-85085162600 (Scopus ID)
Available from: 2020-07-06 Created: 2020-07-06 Last updated: 2022-11-07Bibliographically approved
Kulik, T., Palianytsia, B. & Larsson, M. (2020). Catalytic Pyrolysis of Aliphatic Carboxylic Acids into Symmetric Ketones over Ceria-Based Catalysts: Kinetics, Isotope Effect and Mechanism. Catalysts, 10(2), Article ID 179.
Open this publication in new window or tab >>Catalytic Pyrolysis of Aliphatic Carboxylic Acids into Symmetric Ketones over Ceria-Based Catalysts: Kinetics, Isotope Effect and Mechanism
2020 (English)In: Catalysts, E-ISSN 2073-4344, Vol. 10, no 2, article id 179Article in journal (Refereed) Published
Abstract [en]

Ketonization is a promising way for upgrading bio-derived carboxylic acids from pyrolysis bio-oils, waste oils, and fats to produce high value-added chemicals and biofuels. Therefore, an understanding of its mechanism can help to carry out the catalytic pyrolysis of biomass more efficiently. Here we show that temperature-programmed desorption mass spectrometry (TPD-MS) together with linear free energy relationships (LFERs) can be used to identify catalytic pyrolysis mechanisms. We report the kinetics of the catalytic pyrolysis of deuterated acetic acid and a reaction series of linear and branched fatty acids into symmetric ketones on the surfaces of ceria-based oxides. A structure-reactivity correlation between Taft's steric substituent constants Es* and activation energies of ketonization indicates that this reaction is the sterically controlled reaction. Surface D3-n-acetates transform into deuterated acetone isotopomers with different yield, rate, E-not equal and deuterium kinetic isotope effect (DKIE). The obtained values of inverse DKIE together with the structure-reactivity correlation support a concerted mechanism over ceria-based catalysts. These results demonstrate that analysis of Taft's correlations and using simple equation for estimation of DKIE from TPD-MS data are promising approaches for the study of catalytic pyrolysis mechanisms on a semi-quantitative level.

Keywords
carboxylic acids upgrading, ketonization, deuterated acetic acid, acetone D-isotopomers distribution, H/D exchange, inverse deuterium kinetic isotope effect, kinetic parameters, activation energy, catalytic pyrolysis of biomass, bio-oil
National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-181108 (URN)10.3390/catal10020179 (DOI)000519998900037 ()
Available from: 2020-04-27 Created: 2020-04-27 Last updated: 2022-03-23Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9784-4151

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