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Publications (10 of 139) Show all publications
Banerjee, A., Jay, R. M., Leitner, T., Wang, R.-P., Harich, J., Stefanuik, R., . . . Wernet, P. (2024). Accessing metal-specific orbital interactions in C–H activation with resonant inelastic X-ray scattering. Chemical Science, 15(7), 2398-2409
Open this publication in new window or tab >>Accessing metal-specific orbital interactions in C–H activation with resonant inelastic X-ray scattering
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2024 (English)In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 15, no 7, p. 2398-2409Article in journal (Refereed) Published
Abstract [en]

Photochemically prepared transition-metal complexes are known to be effective at cleaving the strong C–H bonds of organic molecules in room temperature solutions. There is also ample theoretical evidence that the two-way, metal to ligand (MLCT) and ligand to metal (LMCT), charge-transfer between an incoming alkane C–H group and the transition metal is the decisive interaction in the C–H activation reaction. What is missing, however, are experimental methods to directly probe these interactions in order to reveal what determines reactivity of intermediates and the rate of the reaction. Here, using quantum chemical simulations we predict and propose future time-resolved valence-to-core resonant inelastic X-ray scattering (VtC-RIXS) experiments at the transition metal L-edge as a method to provide a full account of the evolution of metal–alkane interactions during transition-metal mediated C–H activation reactions. For the model system cyclopentadienyl rhodium dicarbonyl (CpRh(CO)2), we demonstrate, by simulating the VtC-RIXS signatures of key intermediates in the C–H activation pathway, how the Rh-centered valence-excited states accessible through VtC-RIXS directly reflect changes in donation and back-donation between the alkane C–H group and the transition metal as the reaction proceeds via those intermediates. We benchmark and validate our quantum chemical simulations against experimental steady-state measurements of CpRh(CO)2 and Rh(acac)(CO)2 (where acac is acetylacetonate). Our study constitutes the first step towards establishing VtC-RIXS as a new experimental observable for probing reactivity of C–H activation reactions. More generally, the study further motivates the use of time-resolved VtC-RIXS to follow the valence electronic structure evolution along photochemical, photoinitiated and photocatalytic reactions with transition metal complexes.

National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:su:diva-226121 (URN)10.1039/d3sc04388f (DOI)001142278500001 ()2-s2.0-85182913108 (Scopus ID)
Available from: 2024-02-06 Created: 2024-02-06 Last updated: 2024-04-29Bibliographically approved
Das, S. K., Winghart, M.-O., Han, P., Rana, D., Zhang, Z.-Y., Eckert, S., . . . Odelius, M. (2024). Electronic Fingerprint of the Protonated Imidazole Dimer Probed by X-ray Absorption Spectroscopy. The Journal of Physical Chemistry Letters, 15(5), 1264-1272
Open this publication in new window or tab >>Electronic Fingerprint of the Protonated Imidazole Dimer Probed by X-ray Absorption Spectroscopy
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2024 (English)In: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, Vol. 15, no 5, p. 1264-1272Article in journal (Refereed) Published
Abstract [en]

Protons in low-barrier superstrong hydrogen bonds are typically delocalized between two electronegative atoms. Conventional methods to characterize such superstrong hydrogen bonds are vibrational spectroscopy and diffraction techniques. We introduce soft X-ray spectroscopy to uncover the electronic fingerprints for proton sharing in the protonated imidazole dimer, a prototypical building block enabling effective proton transport in biology and high-temperature fuel cells. Using nitrogen core excitations as a sensitive probe for the protonation status, we identify the X-ray signature of a shared proton in the solvated imidazole dimer in a combined experimental and theoretical approach. The degree of proton sharing is examined as a function of structural variations that modify the shape of the low-barrier potential in the superstrong hydrogen bond. We conclude by showing how the sensitivity to the quantum distribution of proton motion in the double-well potential is reflected in the spectral signature of the shared proton. 

National Category
Physical Chemistry Other Physics Topics
Research subject
Physics; Physical Chemistry
Identifiers
urn:nbn:se:su:diva-226596 (URN)10.1021/acs.jpclett.3c03576 (DOI)001160598400001 ()38278137 (PubMedID)2-s2.0-85184612718 (Scopus ID)
Funder
Swedish Research Council, 2021-04521EU, Horizon 2020, 860553
Available from: 2024-02-14 Created: 2024-02-14 Last updated: 2024-07-04Bibliographically approved
Mosaferi, M., Céolin, D., Rueff, J.-P., Selles, P., Odelius, M., Björneholm, O., . . . Carniato, S. (2024). Fingerprint of Dipole Moment Orientation of Water Molecules in Cu2+ Aqueous Solution Probed by X-ray Photoelectron Spectroscopy. Journal of the American Chemical Society, 146(14), 9836-9850
Open this publication in new window or tab >>Fingerprint of Dipole Moment Orientation of Water Molecules in Cu2+ Aqueous Solution Probed by X-ray Photoelectron Spectroscopy
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2024 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 146, no 14, p. 9836-9850Article in journal (Refereed) Published
Abstract [en]

The electronic structure and geometrical organization of aqueous Cu2+ have been investigated by using X-ray photoelectron spectroscopy (XPS) at the Cu L-edge combined with state-of-the-art ab initio molecular dynamics and a quantum molecular approach designed to simulate the Cu 2p X-ray photoelectron spectrum. The calculations offer a comprehensive insight into the origin of the main peak and satellite features. It is illustrated how the energy drop of the Cu 3d levels (≈7 eV) following the creation of the Cu 2p core hole switches the nature of the highest singly occupied molecular orbitals (MOs) from the dominant metal to the dominant MO nature of water. It is particularly revealed how the repositioning of the Cu 3d levels induces the formation of new bonding (B) and antibonding (AB) orbitals, from which shakeup mechanisms toward the relaxed H-SOMO operate. As highlighted in this study, the appearance of the shoulder near the main peak corresponds to the characteristic signature of shakeup intraligand (1a1 → H-SOMO(1b1)) excitations in water, providing insights into the average dipole moment distribution (≈36°) of the first-shell water molecules surrounding the metal ion and its direct impact on the broadening of the satellite. It is also revealed that the main satellite at 8 eV from the main peak corresponds to (metal/1b2 → H-SOMO(1b1) of water) excitations due to a bonding/antibonding (B/AB) interaction of Cu 3d levels with the deepest valence O2p/H1s 1b2 orbitals of water. This finding underscores the sensitivity of XPS to the electronic structure and orientation of the nearest water molecules around the central ion.

National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:su:diva-228253 (URN)10.1021/jacs.3c14570 (DOI)001193912900001 ()38545903 (PubMedID)2-s2.0-85189001892 (Scopus ID)
Available from: 2024-04-11 Created: 2024-04-11 Last updated: 2024-04-11Bibliographically approved
Marks, K., Erbing, A., Hohmann, L., Chien, T.-E., Yazdi, M. G., Muntwiler, M., . . . Gothelid, M. (2024). Naphthalene Dehydrogenation on Ni(111) in the Presence of Chemisorbed Oxygen and Nickel Oxide. Catalysts, 14(2), Article ID 124.
Open this publication in new window or tab >>Naphthalene Dehydrogenation on Ni(111) in the Presence of Chemisorbed Oxygen and Nickel Oxide
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2024 (English)In: Catalysts, E-ISSN 2073-4344, Vol. 14, no 2, article id 124Article in journal (Refereed) Published
Abstract [en]

Catalyst passivation through carbon poisoning is a common and costly problem as it reduces the lifetime and performance of the catalyst. Adding oxygen to the feed stream could reduce poisoning but may also affect the activity negatively. We have studied the dehydrogenation, decomposition, and desorption of naphthalene co-adsorbed with oxygen on Ni(111) by combining temperature-programmed desorption (TPD), sum frequency generation spectroscopy (SFG), photoelectron spectroscopy (PES), and density functional theory (DFT). Chemisorbed oxygen reduces the sticking of naphthalene and shifts H2 production and desorption to higher temperatures by blocking active Ni sites. Oxygen increases the production of CO and reduces carbon residues on the surface. Chemisorbed oxygen is readily removed when naphthalene is decomposed. Oxide passivates the surface and reduces the sticking coefficient. But it also increases the production of CO dramatically and reduces the carbon residues. Ni2O3 is more active than NiO.

Keywords
dehydrogenation, decomposition, naphthalene, nickel, oxygen, nickel oxide
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:su:diva-227740 (URN)10.3390/catal14020124 (DOI)001172450400001 ()2-s2.0-85187295000 (Scopus ID)
Available from: 2024-03-26 Created: 2024-03-26 Last updated: 2024-03-26Bibliographically approved
Söderström, J., Ghosh, A., Kjellsson, L., Ekholm, V., Tokushima, T., Såthe, C., . . . Gel'mukhanov, F. (2024). Parity violation in resonant inelastic soft x-ray scattering at entangled core holes. Science Advances, 10(7), Article ID eadk3114.
Open this publication in new window or tab >>Parity violation in resonant inelastic soft x-ray scattering at entangled core holes
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2024 (English)In: Science Advances, E-ISSN 2375-2548, Vol. 10, no 7, article id eadk3114Article in journal (Refereed) Published
Abstract [en]

Resonant inelastic x-ray scattering (RIXS) is a major method for investigation of electronic structure and dynamics, with applications ranging from basic atomic physics to materials science. In RIXS applied to inversion-symmetric systems, it has generally been accepted that strict parity selectivity applies in the sub-kilo-electron volt region. In contrast, we show that the parity selection rule is violated in the RIXS spectra of the free homonuclear diatomic O-2 molecule. By analyzing the spectral dependence on scattering angle, we demonstrate that the violation is due to the phase difference in coherent scattering at the two atomic sites, in analogy with Young's double-slit experiment. The result also implies that the interpretation of x-ray absorption spectra for inversion symmetric molecules in this energy range must be revised.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-228273 (URN)10.1126/sciadv.adk3114 (DOI)001189022400006 ()38354244 (PubMedID)2-s2.0-85185243654 (Scopus ID)
Available from: 2024-04-11 Created: 2024-04-11 Last updated: 2024-04-11Bibliographically approved
Das, S. K., Odelius, M. & Banerjee, A. (2024). Simulating non-adiabatic dynamics of photoexcited phenyl azide: Investigating electronic and structural relaxation en route to the formation of phenyl nitrene. Chemistry - A European Journal, 30(7), Article ID e202302178.
Open this publication in new window or tab >>Simulating non-adiabatic dynamics of photoexcited phenyl azide: Investigating electronic and structural relaxation en route to the formation of phenyl nitrene
2024 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 30, no 7, article id e202302178Article in journal (Refereed) Published
Abstract [en]

Excited state molecular dynamics simulations of the photoexcited phenyl azide have been performed. The semi-classical surface hopping approximation has enabled an unconstrained analysis of the electronic and nuclear degrees of freedom which contribute to the molecular dissociation of phenyl azide into phenyl nitrene and molecular nitrogen. The significance of the second singlet excited state in leading the photodissociation has been established through electronic structure calculations, based on multi-configurational schemes, and state population dynamics. The investigations on the structural dynamics have revealed the NN bond separation to be accompanied by synchronous changes in the azide NNN bond angle. The 100 fs simulation results in a nitrene fragment that is electronically excited in the singlet manifold.

Keywords
Azides, Non-adiabatic molecular dynamics, Photolysis, CASSCF, Density functional calculations
National Category
Atom and Molecular Physics and Optics Physical Chemistry
Research subject
Chemical Physics
Identifiers
urn:nbn:se:su:diva-225649 (URN)10.1002/chem.202302178 (DOI)001122324200001 ()37921117 (PubMedID)2-s2.0-85179338455 (Scopus ID)
Available from: 2024-01-22 Created: 2024-01-22 Last updated: 2024-03-11Bibliographically approved
Coates, M. R., Banerjee, A., Jay, R. M., Wernet, P. & Odelius, M. (2024). Theoretical Investigation of Transient Species Following Photodissociation of Ironpentacarbonyl in Ethanol Solution. Inorganic Chemistry, 63(23), 10634-10647
Open this publication in new window or tab >>Theoretical Investigation of Transient Species Following Photodissociation of Ironpentacarbonyl in Ethanol Solution
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2024 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 63, no 23, p. 10634-10647Article in journal (Refereed) Published
Abstract [en]

Photodissociation of ironpentacarbonyl [Fe-1(CO)(5)] in solution generates transient species in different electronic states, which we studied theoretically. From ab initio molecular dynamics simulations in ethanol solution, the closed-shell parent compound Fe-1(CO)(5) is found to interact weakly with the solvent, whereas the irontetracarbonyl [Fe(CO)(4)] species, formed after photodissociation, has a strongly spin-dependent behavior. It coordinates a solvent molecule tightly in the singlet state [Fe-1(CO)(4)] and weakly in the triplet state [Fe-3(CO)(4)]. From the simulations, we have gained insights into intersystem crossing in solvated irontetracarbonyl based on the distinct structural differences induced by the change in multiplicity. Alternative forms of coordination between Fe-1(CO)(4) and functional groups of the ethanol molecule are simulated, and a quantum chemical investigation of the energy landscape for the coordinated irontetracarbonyl gives information about the interconversion of different transient species in solution. Furthermore, insights from the simulations, in which we find evidence of a solvent exchange mechanism, challenge the previously proposed mechanism of chain walking for under-coordinated metal carbonyls in solution.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:su:diva-231257 (URN)10.1021/acs.inorgchem.4c01100 (DOI)001234403700001 ()38804078 (PubMedID)
Available from: 2024-06-20 Created: 2024-06-20 Last updated: 2024-06-20Bibliographically approved
Velasquez, N., B. Nunes, F., Travnikova, O., Ismail, I., Guillemin, R., Martins, J. B., . . . Marchenko, T. (2024). X-ray induced ultrafast charge transfer in thiophene-based conjugated polymers controlled by core-hole clock spectroscopy. Physical Chemistry, Chemical Physics - PCCP, 26(2), 1234-1244
Open this publication in new window or tab >>X-ray induced ultrafast charge transfer in thiophene-based conjugated polymers controlled by core-hole clock spectroscopy
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2024 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 26, no 2, p. 1234-1244Article in journal (Refereed) Published
Abstract [en]

We explore ultrafast charge transfer (CT) resonantly induced by hard X-ray radiation in organic thiophene-based polymers at the sulfur K-edge. A combination of core-hole clock spectroscopy with real-time propagation time-dependent density functional theory simulations gives an insight into the electron dynamics underlying the CT process. Our method provides control over CT by a selective excitation of a specific resonance in the sulfur atom with monochromatic X-ray radiation. Our combined experimental and theoretical investigation establishes that the dominant mechanism of CT in polymer powders and films consists of electron delocalisation along the polymer chain occurring on the low-femtosecond time scale. Ultrafast charge transfer along the polymer chains is triggered by a selective resonant core-excitation of the sulfur atom in P3HT films and powders. Our approach opens perspectives for studies on intra-molecular conductivity in organic molecules.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:su:diva-225808 (URN)10.1039/d3cp04303g (DOI)001125337500001 ()38099819 (PubMedID)2-s2.0-85180122318 (Scopus ID)
Available from: 2024-01-23 Created: 2024-01-23 Last updated: 2024-01-23Bibliographically approved
Hedvall, P., Odelius, M. & Larson, Å. (2023). Charge transfer in sodium iodide collisions. Journal of Chemical Physics, 158(1), Article ID 014305.
Open this publication in new window or tab >>Charge transfer in sodium iodide collisions
2023 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 158, no 1, article id 014305Article in journal (Refereed) Published
Abstract [en]

Sodium iodide (NaI) has, over the years, served as a prototype system in studies of non-adiabatic dynamics. Here, the charge transfer collision reactions Na+ + I− ⇆ Na + I (mutual neutralization and ion-pair formation) are studied using an ab initio approach and the total and differential cross sections are calculated for the reactions. This involves electronic structure calculations on NaI to obtain adiabatic potential energy curves, non-adiabatic and spin–orbit couplings, followed by nuclear dynamics, treated fully quantum mechanically in a strictly diabatic representation. A single avoided crossing at 13.22 a0 dominates the reactions, and the total cross sections are well captured by the semi-classical Landau–Zener model. Compared to the measured ion-pair formation cross section, the calculated cross section is about a factor of two smaller, and the overall shape of the calculated differential cross section is in reasonable agreement with the measured ion-pair formation differential cross section. Treating the Landau–Zener coupling as an empirical parameter of 0.05 eV, the measured total and differential cross sections are well captured when performing fully quantum mechanical cross section calculations including rotational coupling. A semi-empirical spin–orbit coupling model is also investigated, giving satisfactory estimation of the effects of spin–orbit interactions for the reactions. 

National Category
Chemical Sciences
Identifiers
urn:nbn:se:su:diva-214335 (URN)10.1063/5.0131749 (DOI)000907681900002 ()36610951 (PubMedID)2-s2.0-85145606568 (Scopus ID)
Available from: 2023-02-06 Created: 2023-02-06 Last updated: 2023-10-05Bibliographically approved
Banerjee, A., da Cruz, V. V., Ekholm, V., Sathe, C., Rubensson, J.-E., Ignatova, N., . . . Odelius, M. (2023). Simulating fluorine K-edge resonant inelastic x-ray scattering of sulfur hexafluoride and the effect of dissociative dynamics. Physical Review A: covering atomic, molecular, and optical physics and quantum information, 108(2), Article ID 023103.
Open this publication in new window or tab >>Simulating fluorine K-edge resonant inelastic x-ray scattering of sulfur hexafluoride and the effect of dissociative dynamics
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2023 (English)In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 108, no 2, article id 023103Article in journal (Refereed) Published
Abstract [en]

We report on a computational study of resonant inelastic x-ray scattering (RIXS), at different fluorine K-edge resonances of the SF6 molecule, and corresponding nonresonant x-ray emission. Previously measured polarization dependence in RIXS is reproduced and traced back to the local sigma and pi symmetry of the molecular orbitals and corresponding states involved in the RIXS process. Also electron-hole coupling energies are calculated and related to experimentally observed spectator shifts. The role of dissociative S-F bond dynamics is explored to model detuning of RIXS spectra at the |F1s(-1) 6a(1g)(1)> resonance, which shows challenges to accurately reproduce the required steepness for core-excited potential energy surface. We show that the RIXS spectra can only be properly described by considering breaking of the global inversion symmetry of the electronic wave function and core-hole localization, induced by vibronic coupling. Due to the core-hole localization we have symmetry forbidden transitions, which lead to additional resonances and changing width of the RIXS profile.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-227727 (URN)10.1103/PhysRevA.108.023103 (DOI)001176824400001 ()
Available from: 2024-03-26 Created: 2024-03-26 Last updated: 2024-03-26Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-7023-2486

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