1
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Lang SM, Bernhardt TM, Bakker JM, Barnett RN, Landman U. Cluster size dependent coordination of formate to free manganese oxide clusters. Phys Chem Chem Phys 2023; 25:32166-32172. [PMID: 37986571 PMCID: PMC10686260 DOI: 10.1039/d3cp04035f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
The interaction of free manganese oxide clusters, MnxOy+ (x = 1-9, y = 0-12), with formic acid was studied via infrared multiple-photon dissociation (IR-MPD) spectroscopy together with calculations using density functional theory (DFT). Clusters containing only one Mn atom, such as MnO2+ and MnO4+, bind formic acid as an intact molecule in both the cis- and trans-configuration. In contrast, all clusters containing two or more manganese atoms deprotonate the acid's hydroxyl group. The coordination of the resulting formate group is strongly cluster-size-dependent according to supporting DFT calculations for selected model systems. For Mn2O2+ the co-existence of two isomers with the formate bound in a bidentate bridging and chelating configurations, respectively, is found, whereas for Mn2O4+ the bidentate chelating configuration is preferred. In contrast, the bidentate bridging structure is energetically considerably more favorable for Mn4O4+. This binding motif stabilizes the 2D ring structure of the core of the Mn4O4+ cluster with respect to the 3D cubic geometry of the Mn4O4+ cluster core.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany.
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany.
| | - Joost M Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Robert N Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, USA
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, USA
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2
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Lang SM, Bernhardt TM, Bakker JM, Yoon B, Landman U. Vibrational spectroscopy of free di-manganese oxide cluster complexes with di-hydrogen. Mol Phys 2023. [DOI: 10.1080/00268976.2023.2192306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Sandra M. Lang
- Institute for Surface Chemistry and Catalysis, University of Ulm, Ulm, Germany
| | | | - Joost M. Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Nijmegen, The Netherlands
| | - Bokwon Yoon
- School of Physics, Georgia Institute of Technology, Atlanta, USA
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, USA
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3
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Mariñoso Guiu J, Ghejan BA, Bernhardt TM, Bakker JM, Lang SM, Bromley ST. Cluster Beam Study of (MgSiO 3) +-Based Monomeric Silicate Species and Their Interaction with Oxygen: Implications for Interstellar Astrochemistry. ACS Earth Space Chem 2022; 6:2465-2470. [PMID: 36303718 PMCID: PMC9589904 DOI: 10.1021/acsearthspacechem.2c00186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/22/2022] [Accepted: 09/13/2022] [Indexed: 06/10/2023]
Abstract
Silicates are ubiquitously found as small dust grains throughout the universe. These particles are frequently subject to high-energy processes and subsequent condensation in the interstellar medium (ISM), where they are broken up into many ultrasmall silicate fragments. These abundant molecular-sized silicates likely play an important role in astrochemistry. By approximately mimicking silicate dust grain processing occurring in the diffuse ISM by ablation/cooling of a Mg/Si source material in the presence of O2, we observed the creation of stable clusters based on discrete pyroxene monomers (MgSiO3 +), which traditionally have only been considered possible as constituents of bulk silicate materials. Our study suggests that such pyroxene monomer-based clusters could be highly abundant in the ISM from the processing of larger silicate dust grains. A detailed analysis, by infrared multiple-photon dissociation (IR-MPD) spectroscopy and density functional theory (DFT) calculations, reveals the structures and properties of these monomeric silicate species. We find that the clusters interact strongly with oxygen, with some stable cluster isomers having a silicate monomeric core bound to an ozone-like moiety. The general high tendency of these monomeric silicate species to strongly adsorb O2 molecules also suggests that they could be relevant to the observed and unexplained depletion of oxygen in the ISM. We further find clusters where a Mg atom is bound to the MgSiO3 monomer core. These species can be considered as the simplest initial step in monomer-initiated nucleation, indicating that small ionized pyroxenic clusters could also assist in the reformation of larger silicate dust grains in the ISM.
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Affiliation(s)
- Joan Mariñoso Guiu
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Bianca-Andreea Ghejan
- Institute
of Surface Chemistry and Catalysis, Ulm
University, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute
of Surface Chemistry and Catalysis, Ulm
University, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Joost M. Bakker
- Radboud
University, Institute for Molecules and Materials, FELIX Laboratory, 6525 ED Nijmegen, The Netherlands
| | - Sandra M. Lang
- Institute
of Surface Chemistry and Catalysis, Ulm
University, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Stefan T. Bromley
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
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4
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Lang SM, Helzel I, Bernhardt TM, Barnett RN, Landman U. Spin-Gated Selectivity of the Water Oxidation Reaction Mediated by Free Pentameric Ca xMn 5-xO 5+ Clusters. J Am Chem Soc 2022; 144:15339-15347. [PMID: 35943864 DOI: 10.1021/jacs.2c06562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the first preparation of isolated ligand-free CaMn4O5+ gas-phase clusters, as well as other pentameric CaxMn5-xO5+ (x = 0-4) clusters with varying Ca contents, which serve as molecular models of the natural CaMn4O5 inorganic cluster in photosystem II. Ion trap reactivity studies with D2O and H218O reveal a pronounced cluster composition-dependent ability to mediate the oxidation of water to hydrogen peroxide. First-principles density functional theory simulations elucidate the mechanism of water oxidation, proceeding via formation of a terminal oxyl radical followed by oxyl/hydroxy (O/OH) coupling. The critical coupling reaction step entails a single electron transfer from the oxyl radical to the accommodating cluster core with a concurrent O/OH coupling forming an adsorbed OOH intermediate group. The spin-conserving electron transfer step takes place when the spin of the transferred electron is aligned with the spins of the d-electrons of the Mn atoms in the cuboidal high-spin cluster isomer. The d-electrons provide a ferromagnetically ordered environment that facilitates the spin-gated selective electron transfer process, resulting in parallel-spin-exchange stabilization and a lowered transition state barrier for the coupling reaction involving the frontier orbitals of the oxyl and hydroxy reactant intermediates.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Irene Helzel
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Robert N Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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5
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Vaida ME, Rawal TB, Bernhardt TM, Marsh BM, Rahman TS, Leone SR. Nonmetal-to-Metal Transition of Magnesia Supported Au Clusters Affects the Ultrafast Dissociation Dynamics of Adsorbed CH 3Br Molecules. J Phys Chem Lett 2022; 13:4747-4753. [PMID: 35612537 DOI: 10.1021/acs.jpclett.2c00968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The detection of intermediate species and the correlation of their ultrafast dynamics with the morphology and electronic structure of a surface is crucial to fully understand and control heterogeneous photoinduced and photocatalytic reactions. In this work, the ultrafast photodissociation dynamics of CH3Br molecules adsorbed on variable-size Au clusters on MgO/Mo(100) is investigated by monitoring the CH3+ transient evolution using a pump-probe technique in conjunction with surface mass spectrometry. Furthermore, extreme-UV photoemission spectroscopy in combination with theoretical calculations is employed to study the electronic structure of the Au clusters on MgO/Mo(100). Changes in the ultrafast dynamics of the CH3+ fragment are correlated with the electronic structure of Au as it evolves from monomers to small nonmetallic clusters to larger nanoparticles with a metallic character. This work provides a new avenue to a detailed understanding of how surface-photoinduced chemical reactions are influenced by the composition and electronic structure of the surface.
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Affiliation(s)
- Mihai E Vaida
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
- Renewable Energy and Chemical Transformations Cluster, University of Central Florida, Orlando, Florida 32816, United States
| | - Takat B Rawal
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, 89069 Ulm, Germany
| | - Brett M Marsh
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
- Renewable Energy and Chemical Transformations Cluster, University of Central Florida, Orlando, Florida 32816, United States
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Lang SM, Zimmermann N, Bernhardt TM, Barnett RN, Yoon B, Landman U. Size, Stoichiometry, Dimensionality, and Ca Doping of Manganese Oxide-Based Water Oxidation Clusters: An Oxyl/Hydroxy Mechanism for Oxygen-Oxygen Coupling. J Phys Chem Lett 2021; 12:5248-5255. [PMID: 34048261 DOI: 10.1021/acs.jpclett.1c01299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Gas-phase ion-trap reactivity experiments and density functional simulations reveal that water oxidation to H2O2 mediated by (calcium) manganese oxide clusters proceeds via formation of a terminal oxyl radical followed by oxyl/hydroxy O-O coupling. This mechanism is predicted to be energetically feasible for Mn2Oy+ (y = 2-4) and the binary CaMn3O4+, in agreement with the experimental observations. In contrast, the reaction does not proceed for the tetramanganese oxides Mn4Oy+ (y = 4-6) under these experimental conditions. This is attributed to the high fluxionality of the tetramanganese clusters, resulting in the instability of the terminal oxyl radical as well as an energetically unfavorable change of the spin state required for H2O2 formation. Ca doping, yielding a symmetry-broken lower-symmetry three-dimensional (3D) CaMn3O4+ cluster, results in structural stabilization of the oxyl radical configuration, accompanied by a favorable coupling between potential energy surfaces with different spin states, thus enabling the cluster-mediated water oxidation reaction and H2O2 formation.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, 89069 Ulm, Germany
| | - Nina Zimmermann
- Institute of Surface Chemistry and Catalysis, University of Ulm, 89069 Ulm, Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, 89069 Ulm, Germany
| | - Robert N Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Bokwon Yoon
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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7
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Lang SM, Bernhardt TM, Bakker JM, Barnett RN, Landman U. Cluster Size Dependent Interaction of Free Manganese Oxide Clusters with Acetic Acid and Methyl Acetate. J Phys Chem A 2021; 125:4435-4445. [PMID: 33988993 DOI: 10.1021/acs.jpca.1c03195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have employed infrared multiple-photon dissociation (IR-MPD) spectroscopy together with density functional theory (DFT) calculations to study the interaction of series of subnanometer sized manganese oxide clusters, MnxOy+ (x = 1-6, y = 0-9) with acetic acid (HOAc) and methyl acetate (MeOAc). Reaction with HOAc leads to strongly cluster size and composition dependent IR-MPD spectra, indicating molecular adsorption on MnOx+ clusters and thermodynamically favorable but kinetically hampered HOAc dissociation (deprotonation) on Mn2O4+ and Mn3O5+. Other cluster sizes exhibit the preferred formation of a dissociative bidentate chelating structure. In contrast to HOAc, all clusters bind MeOAc via the carbonyl group as an intact molecule, and dissociation appears to be kinetically hindered under the given experimental conditions.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Joost M Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Robert N Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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8
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Mravak A, Krstić M, Lang SM, Bernhardt TM, Bonačić‐Koutecký V. Intrazeolite CO Methanation by Small Ruthenium Carbonyl Complexes: Translation from Free Clusters into the Cage. ChemCatChem 2020. [DOI: 10.1002/cctc.202000716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Antonija Mravak
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
| | - Marjan Krstić
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
- Department of Physics Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
| | - Sandra M. Lang
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Vlasta Bonačić‐Koutecký
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
- Interdisciplinary Center for Advanced Science and Technology (ICAST) at University of Split Meštrovićevo šetalište 45 21000 Split Croatia
- Chemistry Department Humboldt University of Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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9
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Mravak A, Krstić M, Lang SM, Bernhardt TM, Bonačić‐Koutecký V. Intrazeolite CO Methanation by Small Ruthenium Carbonyl Complexes: Translation from Free Clusters into the Cage. ChemCatChem 2020. [DOI: 10.1002/cctc.202001092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Antonija Mravak
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
| | - Marjan Krstić
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
- Department of Physics Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
| | - Sandra M. Lang
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Vlasta Bonačić‐Koutecký
- Center of Excellence for Science and Technology - Integration of Mediterranean region (STIM) Faculty of Science University of Split Ruđera Boškovića 33 21000 Split Croatia
- Interdisciplinary Center for Advanced Science and Technology (ICAST) at University of Split Meštrovićevo šetalište 45 21000 Split Croatia
- Chemistry Department Humboldt University of Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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10
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Lang SM, Bernhardt TM, Bakker JM, Barnett RN, Landman U. Energetic Stabilization of Carboxylic Acid Conformers by Manganese Atoms and Clusters. J Phys Chem A 2020; 124:4990-4997. [DOI: 10.1021/acs.jpca.0c03315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Joost M. Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Robert N. Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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11
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Abstract
The interaction of manganese oxide clusters MnxOy+ (x = 2-5, y ≥ x) with CO2 is studied via infrared multiple-photon dissociation spectroscopy (IR-MPD) in the spectral region of 630-1860 cm-1. Along with vibrational modes of the manganese oxide cluster core, two bands are observed around 1200-1450 cm-1 and they are assigned to the characteristic Fermi resonance of CO2 arising from anharmonic coupling between the symmetric stretch vibration and the overtone of the bending mode. The spectral position of the lower frequency band depends on the cluster size and the number of adsorbed CO2 molecules, whereas the higher frequency band is largely unaffected. Despite these effects, the observation of the Fermi dyad indicates only a small perturbation of the CO2 molecule. This finding is confirmed by the theoretical investigation of Mn2O2(CO2)+ revealing only small orbital mixing between the dimanganese oxide cluster and CO2, indicative of mainly electrostatic interaction.
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Affiliation(s)
- Nina Zimmermann
- Institute of Surface Chemistry and Catalysis , University of Ulm , 89069 Ulm , Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis , University of Ulm , 89069 Ulm , Germany
| | - Joost M Bakker
- Radboud University , Institute of Molecules and Materials, FELIX Laboratory , Toernooiveld 7 , 6525 ED Nijmegen , The Netherlands
| | - Robert N Barnett
- School of Physics , Georgia Institute of Technology , Atlanta , Georgia 30332-0430 , United States
| | - Uzi Landman
- School of Physics , Georgia Institute of Technology , Atlanta , Georgia 30332-0430 , United States
| | - Sandra M Lang
- Institute of Surface Chemistry and Catalysis , University of Ulm , 89069 Ulm , Germany
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12
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Zimmermann N, Bernhardt TM, Bakker JM, Landman U, Lang SM. Infrared photodissociation spectroscopy of di-manganese oxide cluster cations. Phys Chem Chem Phys 2019; 21:23922-23930. [PMID: 31661104 DOI: 10.1039/c9cp04586d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Infrared multiple-photon dissociation (IR-MPD) spectroscopy and density functional theory (DFT) calculations have been employed to elucidate the geometric structure of a series of di-manganese oxide clusters Mn2Ox+ (x = 4-7). The theoretical exploration predicts that all investigated clusters contain a rhombus-like Mn2O2 core with up to four, terminally bound, oxygen atoms. The short Mn-O bond length of the terminal oxygen atoms of ≤1.58 Å indicates triple bond character instead of oxyl radical formation. However, the IR-MPD spectra reveal that higher energy isomers with up to two O2 molecules η2-coordinated to the cluster core can be kinetically trapped under the given experimental conditions. In these complexes, all O2 units are activated to superoxide species. In addition, the sequential increase of the oxygen content in the cluster allows for a controlled increase of the positive charge localized on the Mn atoms reaching a maximum for Mn2O7+.
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Affiliation(s)
- Nina Zimmermann
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany.
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13
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Lang SM, Bernhardt TM, Bakker JM, Yoon B, Landman U. Co-adsorption of O 2 and C 2H 4 on a Free Gold Dimer Probed via Infrared Photodissociation Spectroscopy. J Am Soc Mass Spectrom 2019; 30:1895-1905. [PMID: 31300975 DOI: 10.1007/s13361-019-02259-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/04/2019] [Accepted: 05/26/2019] [Indexed: 06/10/2023]
Abstract
Infrared multiple photon dissociation (IR-MPD) spectroscopy in conjunction with density functional theory (DFT) calculations has been employed to study the activation of molecular oxygen and ethylene co-adsorbed on a free gold dimer cation Au2+. Both studied complexes, Au2O2(C2H4)+ and Au2O2(C2H4)2+, show distinct features of both intact O2 and ethylene co-adsorbed on the cluster. However, the ethylene C=C double bond is activated, increasing in length by up to 0.07 Å compared with the free molecule, and the red shift of the O-O vibration frequency increases with the number of adsorbed ethylene molecules, indicating a small but increasing activation of the O-O bond. The small O2 activation and the rather weak interaction between O2 and C2H4 are also reflected in the calculated electronic structure of the co-adsorption complexes which shows only a small occupation of the empty anti-bonding O2 2π*2p orbital as well as the localization of most of the Kohn-Sham orbitals on O2 and C2H4, respectively, with only limited mixing between O2 and C2H4 orbitals. The results are compared with theoretical studies on neutral AuxO2(C2H4) (x = 3, 5, 7, 9) complexes.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069, Ulm, Germany.
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA.
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069, Ulm, Germany
| | - Joost M Bakker
- Radboud University Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, Netherlands
| | - Bokwon Yoon
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA
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14
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Lang SM, Bernhardt TM, Bakker JM, Yoon B, Landman U. Methanol C–O Bond Activation by Free Gold Clusters Probed via Infrared Photodissociation Spectroscopy. Z PHYS CHEM 2019. [DOI: 10.1515/zpch-2018-1368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The activation of methanol (CD3OD and CD3OH) by small cationic gold clusters has been investigated via infrared multiphoton dissociation (IR-MPD) spectroscopy in the 615–1760 cm−1 frequency range. The C–O stretch mode around 925 cm−1 and a coupled CD3 deformation/C–O stretch mode around 1085 cm−1 are identified to be sensitive to the interaction between methanol and the gold clusters, whereas all other modes in the investigated spectral region remain unaffected. Based on the spectral shift of these modes, the largest C–O bond activation is observed for the mono-gold Au(CD3OD)+ cluster. This activation decreases with increasing the cluster size (number of gold atoms) and the number of adsorbed methanol molecules. Supporting density functional theory (DFT) calculations reveal that the C–O bond activation is caused by a methanol to gold charge donation, whereas the C–D and O–D bonds are not significantly activated by this process. The results are discussed with respect to previous experimental and theoretical investigations of neutral and cationic gold-methanol complexes focusing on the C–O stretch mode.
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Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm , Albert-Einstein-Allee 47 , 89069 Ulm , Germany
- School of Physics, Georgia Institute of Technology , Atlanta , GA 30332-0430, USA
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm , Albert-Einstein-Allee 47 , 89069 Ulm , Germany
| | - Joost M. Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory , Toernooiveld 7c , 6525 ED Nijmegen , The Netherlands
| | - Bokwon Yoon
- School of Physics, Georgia Institute of Technology , Atlanta , GA 30332-0430, USA
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology , Atlanta , GA 30332-0430, USA
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15
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Mauthe S, Fleischer I, Bernhardt TM, Lang SM, Barnett RN, Landman U. A Gas‐Phase Ca
n
Mn
4−
n
O
4
+
Cluster Model for the Oxygen‐Evolving Complex of Photosystem II. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201903738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Silvia Mauthe
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Irene Fleischer
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Sandra M. Lang
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Robert N. Barnett
- School of Physics Georgia Institute of Technology Atlanta Georgia 30332-0430 USA
| | - Uzi Landman
- School of Physics Georgia Institute of Technology Atlanta Georgia 30332-0430 USA
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16
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Mauthe S, Fleischer I, Bernhardt TM, Lang SM, Barnett RN, Landman U. A Gas‐Phase Ca
n
Mn
4−
n
O
4
+
Cluster Model for the Oxygen‐Evolving Complex of Photosystem II. Angew Chem Int Ed Engl 2019; 58:8504-8509. [DOI: 10.1002/anie.201903738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Silvia Mauthe
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Irene Fleischer
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Sandra M. Lang
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Robert N. Barnett
- School of Physics Georgia Institute of Technology Atlanta Georgia 30332-0430 USA
| | - Uzi Landman
- School of Physics Georgia Institute of Technology Atlanta Georgia 30332-0430 USA
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17
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Lang SM, Bernhardt TM, Bakker JM, Yoon B, Landman U. The interaction of ethylene with free gold cluster cations: infrared photodissociation spectroscopy combined with electronic and vibrational structure calculations. J Phys Condens Matter 2018; 30:504001. [PMID: 30465551 DOI: 10.1088/1361-648x/aaeafd] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interaction of ethylene with free gold clusters of different sizes and charge states has been previously shown theoretically to involve two different adsorption modes of the C2H4 molecule, namely: the di-σ- and π-bonded ethylene adsorption configurations. Here, we present the first experimental investigation of the structure of a series of gas-phase gold-ethylene complexes, [Formula: see text]. By employing infrared multiple-photon dissociation spectroscopy in conjunction with first-principles calculations it is revealed that up to three C2H4 molecules preferably bind to gold cations in a π-bonded configuration. The binding of all ethylene molecules is found to be dominated by partial electron donation from the ethylene molecules to the gold clusters leading to an activation of the C-C bond. The cooperative action of multiple coadsorbed C2H4 on [Formula: see text] is shown to enable additional charge back-donation and an enhanced C-C bond activation. In contrast, the strong C-H bond is not weakened and the experimental spectra do not give any indication for C-H bond dissociation. The possible correlations of the C-C bond stretch vibration with the C-C bond length and the net charge transfer are discussed.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany. School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, United States of America
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18
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Jochmann K, Bernhardt TM. The influence of metal cluster lattices on the screening of image potential state electrons on graphene. J Chem Phys 2018; 149:164706. [DOI: 10.1063/1.5052643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kira Jochmann
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
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19
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Abstract
The thermal decomposition of free cationic iron-sulfur clusters FexSy+ (x = 0-7, y = 0-9) is investigated by collisional post-heating in the temperature range between 300 and 1000 K. With increasing temperature the preferential formation of stoichiometric FexSy+ (y = x) or near stoichiometric FexSy+ (y = x ± 1) clusters is observed. In particular, Fe4S4+ represents the most abundant product up to 600 K, Fe3S3+ and Fe3S2+ are preferably formed between 600 K and 800 K, and Fe2S2+ clearly dominates the cluster distribution above 800 K. These temperature dependent fragment distributions suggest a sequential fragmentation mechanism, which involves the loss of sulfur and iron atoms as well as FeS units, and indicate the particular stability of Fe2S2+. The potential fragmentation pathways are discussed based on first principles calculations and a mechanism involving the isomerization of the cluster prior to fragmentation is proposed. The fragmentation behavior of the iron-sulfur clusters is in marked contrast to the previously reported thermal dissociation of analogous iron-oxide clusters, which resulted in the release of O2 molecules only, without loss of metal atoms and without any tendency to form particular prominent and stable FexOy+ clusters at high temperatures.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany.
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20
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Vaida ME, Bernhardt TM. Tuning the ultrafast photodissociation dynamics of CH 3 Br on ultrathin MgO films by reducing the layer thickness to the 2D limit. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Lang SM, Bernhardt TM, Chernyy V, Bakker JM, Barnett RN, Landman U. Selective C−H Bond Cleavage in Methane by Small Gold Clusters. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201706009] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis University of Ulm Albert-Einstein-Allee 47 89069 Ulm Germany
| | - Valeriy Chernyy
- Institute for Molecules and Materials FELIX Laboratory Radboud University 6525 ED Nijmegen The Netherlands
| | - Joost M. Bakker
- Institute for Molecules and Materials FELIX Laboratory Radboud University 6525 ED Nijmegen The Netherlands
| | - Robert N. Barnett
- School of Physics Georgia Institute of Technology Atlanta GA 30332-0430 USA
| | - Uzi Landman
- School of Physics Georgia Institute of Technology Atlanta GA 30332-0430 USA
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22
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Lang SM, Bernhardt TM, Chernyy V, Bakker JM, Barnett RN, Landman U. Selective C-H Bond Cleavage in Methane by Small Gold Clusters. Angew Chem Int Ed Engl 2017; 56:13406-13410. [PMID: 28869784 DOI: 10.1002/anie.201706009] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/21/2017] [Indexed: 11/06/2022]
Abstract
Methane represents the major constituent of natural gas. It is primarily used only as a source of energy by means of combustion, but could also serve as an abundant hydrocarbon feedstock for high quality chemicals. One of the major challenges in catalysis research nowadays is therefore the development of materials that selectively cleave one of the four C-H bonds of methane and thus make it amenable for further chemical conversion into valuable compounds. By employing infrared spectroscopy and first-principles calculations it is uncovered herein that the interaction of methane with small gold cluster cations leads to selective C-H bond dissociation and the formation of hydrido methyl complexes, H-Aux+ -CH3 . The distinctive selectivity offered by these gold clusters originates from a fine interplay between the closed-shell nature of the d states and relativistic effects in gold. Such fine balance in fundamental interactions could prove to be a tunable feature in the rational design of a catalyst.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069, Ulm, Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069, Ulm, Germany
| | - Valeriy Chernyy
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, 6525, ED, Nijmegen, The Netherlands
| | - Joost M Bakker
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, 6525, ED, Nijmegen, The Netherlands
| | - Robert N Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332-0430, USA
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23
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Lang SM, Bernhardt TM, Kiawi DM, Bakker JM, Barnett RN, Landman U. Cluster size and composition dependent water deprotonation by free manganese oxide clusters. Phys Chem Chem Phys 2016; 18:15727-37. [DOI: 10.1039/c6cp00779a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrational spectroscopy and first-principles calculations reveal basic concepts of the interaction between manganese oxide clusters and water which could aid the future design of artificial water-splitting molecular catalysts.
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Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis
- University of Ulm
- 89069 Ulm
- Germany
- Institute of Chemical Engineering
| | | | - Denis M. Kiawi
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Joost M. Bakker
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | | | - Uzi Landman
- School of Physics
- Georgia Institute of Technology
- Atlanta
- USA
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24
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Lang SM, Bernhardt TM, Kiawi DM, Bakker JM, Barnett RN, Landman U. The Interaction of Water with Free Mn
4
O
4
+
Clusters: Deprotonation and Adsorption‐Induced Structural Transformations. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506294] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert‐Einstein‐Allee 47, 89069 Ulm (Germany)
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert‐Einstein‐Allee 47, 89069 Ulm (Germany)
| | - Denis M. Kiawi
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen (The Netherlands)
- Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (The Netherlands)
| | - Joost M. Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen (The Netherlands)
| | - Robert N. Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332‐0430 (United States)
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332‐0430 (United States)
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25
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Lang SM, Bernhardt TM, Kiawi DM, Bakker JM, Barnett RN, Landman U. The Interaction of Water with Free Mn4O4+Clusters: Deprotonation and Adsorption-Induced Structural Transformations. Angew Chem Int Ed Engl 2015; 54:15113-7. [DOI: 10.1002/anie.201506294] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/24/2015] [Indexed: 11/11/2022]
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26
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Lang SM, Fleischer I, Bernhardt TM, Barnett RN, Landman U. Low-Temperature CO Oxidation Catalyzed by Free Palladium Clusters: Similarities and Differences to Pd Surfaces and Supported Particles. ACS Catal 2015. [DOI: 10.1021/cs5016222] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sandra M. Lang
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Irene Fleischer
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Robert N. Barnett
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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27
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Lang SM, Förtig SU, Bernhardt TM, Krstić M, Bonačić-Koutecký V. Gas-phase synthesis and structure of Wade-type ruthenium carbonyl and hydrido carbonyl clusters. J Phys Chem A 2014; 118:8356-9. [PMID: 24571192 DOI: 10.1021/jp501242c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The gas-phase reaction of size-selected Ru(n)(+) (n = 4-6) clusters with CO in an ion trap yields only one specific ruthenium carbonyl complex for each cluster size, Ru4(CO)14(+), Ru5(CO)16(+), and Ru6(CO)18(+). First-principles density functional theory calculations reveal structures for these hitherto unknown carbonyl compounds that are in perfect agreement with the geometries predicted by Wade's electron counting rules. Furthermore, reactions with D2 show that for Ru4(+) and Ru6(+), CO molecules can be partially replaced by D2 to form hydrido carbonyl complexes while preserving the total ligand count corresponding to the Wade cluster sizes.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm , Albert-Einstein-Allee 47, 89069 Ulm, Germany
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28
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Lang SM, Bernhardt TM, Krstić M, Bonačić-Koutecký V. Water activation by small free ruthenium oxide clusters. Phys Chem Chem Phys 2014; 16:26578-83. [DOI: 10.1039/c4cp02366h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Lang SM, Fleischer I, Bernhardt TM, Barnett RN, Landman U. Size-Dependent Self-Limiting Oxidation of Free Palladium Clusters. J Phys Chem A 2014; 118:8572-82. [DOI: 10.1021/jp502736p] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sandra M. Lang
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Irene Fleischer
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute
of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Robert N. Barnett
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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30
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Lang SM, Bernhardt TM, Krstić M, Bonačić-Koutecký V. Inside Cover: The Origin of the Selectivity and Activity of Ruthenium-Cluster Catalysts for Fuel-Cell Feed-Gas Purification: A Gas-Phase Approach (Angew. Chem. Int. Ed. 21/2014). Angew Chem Int Ed Engl 2014. [DOI: 10.1002/anie.201401131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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Lang SM, Bernhardt TM, Krstić M, Bonačić-Koutecký V. Innentitelbild: Ursprung der Selektivität und Aktivität von Ru-Clusterkatalysatoren für die Brennstoffzellen-Prozessgasreinigung: ein Gasphasenansatz (Angew. Chem. 21/2014). Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201401131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Lang SM, Bernhardt TM, Krstić M, Bonačić-Koutecký V. The origin of the selectivity and activity of ruthenium-cluster catalysts for fuel-cell feed-gas purification: a gas-phase approach. Angew Chem Int Ed Engl 2014; 53:5467-71. [PMID: 24803209 DOI: 10.1002/anie.201310134] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/04/2014] [Indexed: 11/12/2022]
Abstract
Gas-phase ruthenium clusters Ru(n)(+) (n=2-6) are employed as model systems to discover the origin of the outstanding performance of supported sub-nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed-gas purification for advanced fuel-cell applications. Using ion-trap mass spectrometry in conjunction with first-principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre-formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru-atom sites with a low number of metal-metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl-type intermediate.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm (Germany)
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33
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Lang SM, Bernhardt TM, Krstić M, Bonačić-Koutecký V. Ursprung der Selektivität und Aktivität von Ru-Clusterkatalysatoren für die Brennstoffzellen-Prozessgasreinigung: ein Gasphasenansatz. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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34
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Vaida ME, Bernhardt TM. Surface-Aligned Femtochemistry: Molecular Reaction Dynamics on Oxide Surfaces. Springer Series in Chemical Physics 2014. [DOI: 10.1007/978-3-319-02051-8_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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35
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Lang SM, Fleischer I, Bernhardt TM, Barnett RN, Landman U. Dimensionality dependent water splitting mechanisms on free manganese oxide clusters. Nano Lett 2013; 13:5549-5555. [PMID: 24164444 DOI: 10.1021/nl4031456] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The interaction of ligand-free manganese oxide nanoclusters with water is investigated, aiming at uncovering phenomena which could aid the design of artificial water-splitting molecular catalysts. Gas phase measurements in an ion trap in conjunction with first-principles calculations provide new mechanistic insight into the water splitting process mediated by bi- and tetra-nuclear singly charged manganese oxide clusters, Mn2O2(+) and Mn4O4(+). In particular, a water-induced dimensionality change of Mn4O4(+) is predicted, entailing transformation from a two-dimensional ring-like ground state structure of the bare cluster to a cuboidal octa-hydroxy-complex for the hydrated one. It is further predicted that the water splitting process is facilitated by the cluster dimensionality crossover. The vibrational spectra calculated for species occurring along the predicted pathways of the reaction of Mn4O4(+) with water provide the impetus for future explorations, including vibrational spectroscopic experiments.
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Affiliation(s)
- Sandra M Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm , Albert-Einstein-Allee 47, 89069 Ulm, Germany
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36
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Lang SM, Frank A, Bernhardt TM. Comparison of methane activation and catalytic ethylene formation on free gold and palladium dimer cations: product binding determines the catalytic turnover. Catal Sci Technol 2013. [DOI: 10.1039/c3cy00286a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Lang SM, Fleischer I, Bernhardt TM, Barnett RN, Landman U. Pd6O4+: An Oxidation Resistant yet Highly Catalytically Active Nano-oxide Cluster. J Am Chem Soc 2012; 134:20654-9. [DOI: 10.1021/ja308189w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Samdra M. Lang
- Institute of Surface Chemistry
and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Irene Fleischer
- Institute of Surface Chemistry
and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry
and Catalysis, University of Ulm, Albert-Einstein-Allee
47, 89069 Ulm, Germany
| | - Robert N. Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430,
United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430,
United States
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38
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Vaida ME, Bernhardt TM. Surface-aligned femtochemistry: Photoinduced reaction dynamics of CH3I and CH3Br on MgO(100). Faraday Discuss 2012; 157:437-49; discussion 475-500. [DOI: 10.1039/c2fd20104f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Lang SM, Schnabel T, Bernhardt TM. Reactions of carbon monoxide with free palladium oxide clusters: strongly size dependent competition between adsorption and combustion. Phys Chem Chem Phys 2012; 14:9364-70. [DOI: 10.1039/c2cp23976k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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42
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Popolan DM, Bernhardt TM. Communication: CO oxidation by silver and gold cluster cations: Identification of different active oxygen species. J Chem Phys 2011; 134:091102. [DOI: 10.1063/1.3563631] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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43
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Popolan DM, Nössler M, Mitrić R, Bernhardt TM, Bonačić-Koutecký V. Tuning Cluster Reactivity by Charge State and Composition: Experimental and Theoretical Investigation of CO Binding Energies to AgnAum+/− (n + m = 3). J Phys Chem A 2011; 115:951-9. [DOI: 10.1021/jp106884p] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Denisia M. Popolan
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Melanie Nössler
- Chemistry Department, Humboldt University of Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Roland Mitrić
- Physics Department, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Vlasta Bonačić-Koutecký
- Chemistry Department, Humboldt University of Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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Lang SM, Bernhardt TM. Methane activation and partial oxidation on free gold and palladium clusters: Mechanistic insights into cooperative and highly selective cluster catalysis. Faraday Discuss 2011; 152:337-51; discussion 393-413. [DOI: 10.1039/c1fd00025j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Vaida ME, Tchitnga R, Bernhardt TM. Femtosecond time-resolved photodissociation dynamics of methyl halide molecules on ultrathin gold films. Beilstein J Nanotechnol 2011; 2:618-27. [PMID: 22003467 PMCID: PMC3190631 DOI: 10.3762/bjnano.2.65] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 09/16/2011] [Indexed: 05/12/2023]
Abstract
The photodissociation of small organic molecules, namely methyl iodide, methyl bromide, and methyl chloride, adsorbed on a metal surface was investigated in real time by means of femtosecond-laser pump-probe mass spectrometry. A weakly interacting gold surface was employed as substrate because the intact adsorption of the methyl halide molecules was desired prior to photoexcitation. The gold surface was prepared as an ultrathin film on Mo(100). The molecular adsorption behavior was characterized by coverage dependent temperature programmed desorption spectroscopy. Submonolayer preparations were irradiated with UV light of 266 nm wavelength and the subsequently emerging methyl fragments were probed by photoionization and mass spectrometric detection. A strong dependence of the excitation mechanism and the light-induced dynamics on the type of molecule was observed. Possible photoexcitation mechanisms included direct photoexcitation to the dissociative A-band of the methyl halide molecules as well as the attachment of surface-emitted electrons with transient negative ion formation and subsequent molecular fragmentation. Both reaction pathways were energetically possible in the case of methyl iodide, yet, no methyl fragments were observed. As a likely explanation, the rapid quenching of the excited states prior to fragmentation is proposed. This quenching mechanism could be prevented by modification of the gold surface through pre-adsorption of iodine atoms. In contrast, the A-band of methyl bromide was not energetically directly accessible through 266 nm excitation. Nevertheless, the one-photon-induced dissociation was observed in the case of methyl bromide. This was interpreted as being due to a considerable energetic down-shift of the electronic A-band states of methyl bromide by about 1.5 eV through interaction with the gold substrate. Finally, for methyl chloride no photofragmentation could be detected at all.
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Affiliation(s)
- Mihai E Vaida
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Robert Tchitnga
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
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Vaida ME, Bernhardt TM. Surface pump-probe femtosecond-laser mass spectrometry: time-, mass-, and velocity-resolved detection of surface reaction dynamics. Rev Sci Instrum 2010; 81:104103. [PMID: 21034102 DOI: 10.1063/1.3488098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A detailed account of the experimental methodology of surface pump-probe femtosecond-laser mass spectrometry is presented. This recently introduced technique enables the direct time-resolved investigation of surface reaction dynamics by monitoring the mass and the relative velocity of intermediates and products of a photoinduced surface reaction via multiphoton ionization. As a model system, the photodissociation dynamics of methyl iodide adsorbed at submonolayer coverage on magnesia ultrathin films is investigated. The magnesia surface preparation and characterization as well as the pulsed deposition of methyl iodide are described. The femtosecond-laser excitation (pump) and, in particular, the resonant multiphoton ionization surface detection (probe) schemas are discussed in detail. Results of pump-probe time-resolved methyl and iodine atom detection experiments are presented and the potential of this method for velocity-resolved photofragment analysis is evaluated.
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Affiliation(s)
- Mihai E Vaida
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
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Vaida ME, Bernhardt TM. Surface-Aligned Femtochemistry: Real-Time Dynamics of Photoinduced I2Formation from CD3I on MgO(100). Chemphyschem 2010; 11:804-7. [DOI: 10.1002/cphc.200900920] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Popolan DM, Nößler M, Mitrić R, Bernhardt TM, Bonačić-Koutecký V. Composition dependent adsorption of multiple CO molecules on binary silver–gold clusters AgnAum+ (n + m = 5): theory and experiment. Phys Chem Chem Phys 2010; 12:7865-73. [DOI: 10.1039/b924022e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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