1
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Merriles DM, Barrera-Casas Y, Knapp AS, Morse MD. Adiabatic ionization energies of RuC, RhC, OsC, IrC, and PtC. J Chem Phys 2024; 160:084303. [PMID: 38391018 DOI: 10.1063/5.0194848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 01/24/2024] [Indexed: 02/24/2024] Open
Abstract
The ionization energies (IEs) of RuC, RhC, OsC, IrC, and PtC are assigned by the measurement of their two-photon ionization thresholds. Although late transition metal-carbon bonds are of major importance in organometallic chemistry and catalysis, accurate and precise fundamental thermochemical data on these chemical bonds are mainly lacking in the literature. Based on their two-photon ionization thresholds, in this work, we assign IE(RuC) = 7.439(40) eV, IE(RhC) = 7.458(32) eV, IE(OsC) = 8.647(25) eV, IE(IrC) = 8.933(74) eV, and IE(PtC) = 9.397(32) eV. These experimentally derived IEs are further confirmed through quantum chemical calculations using coupled-cluster single double perturbative triple methods that are extrapolated to the complete basis set limit using a three-parameter mixed Gaussian/exponential extrapolation scheme and corrected for spin-orbit effects using a semiempirical method. The electronic structure and chemical bonding of these MC species are discussed in the context of these ionization energy measurements. The IEs of RuC, RhC, OsC, and IrC closely mirror the IEs of the corresponding transition metal atoms, suggesting that for these species, the (n + 1)s electrons of the transition metals are not significantly involved in chemical bonding.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | | | - Annie S Knapp
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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2
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Abstract
Predissociation thresholds corresponding to dissociation at ground state separated atom limits (SALs) have been recorded in this group for more than 100 d- and f-block metal-containing molecules. The metal atom electronic degeneracies in these molecules generate a dense manifold of electronic states that allow high-lying vibronic levels to couple to pathways leading to dissociation. However, CrN, CuB, and AuB fail to dissociate at their ground SAL. Instead, the molecules remain bound at energies that far surpass their bond dissociation energies (BDEs), and their bonds break only when excited at or above an excited SAL. Sharp predissociation thresholds at excited SALs nevertheless allowed BDEs to be derived: D0(CrN): 3.941(22) eV; D0(CuB): 2.26(15) eV; D0(Au11B): 3.724(3) eV. A previous measurement of D0(AlCr) is re-evaluated as dissociating to a higher energy limit, giving a revised value of D0(AlCr) = 1.32(2) eV. A discussion of this physical behavior is presented.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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3
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Merriles DM, Knapp AS, Barrera-Casas Y, Sevy A, Sorensen JJ, Morse MD. Bond dissociation energies of diatomic transition metal nitrides. J Chem Phys 2023; 158:084308. [PMID: 36859107 DOI: 10.1063/5.0141182] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Resonant two-photon ionization (R2PI) spectroscopy has been used to measure the bond dissociation energies (BDEs) of the diatomic transition metal nitrides ScN, TiN, YN, MoN, RuN, RhN, HfN, OsN, and IrN. Of these, the BDEs of only TiN and HfN had been previously measured. Due to the many ways electrons can be distributed among the d orbitals, these molecules possess an extremely high density of electronic states near the ground separated atom limit. Spin-orbit and nonadiabatic interactions couple these states quite effectively, so that the molecules readily find a path to dissociation when excited above the ground separated atom limit. The result is a sharp drop in ion signal in the R2PI spectrum when the molecule is excited above this limit, allowing the BDE to be readily measured. Using this method, the values D0(ScN) = 3.905(29) eV, D0(TiN) = 5.000(19) eV, D0(YN) = 4.125(24) eV, D0(MoN) = 5.220(4) eV, D0(RuN) = 4.905(3) eV, D0(RhN) = 3.659(32) eV, D0(HfN) = 5.374(4) eV, D0(OsN) = 5.732(3) eV, and D0(IrN) = 5.115(4) eV are obtained. To support the experimental findings, ab initio coupled-cluster calculations extrapolated to the complete basis set limit (CBS) were performed. With a semiempirical correction for spin-orbit effects, these coupled-cluster single double triple-CBS calculations give a mean absolute deviation from the experimental BDE values of 0.20 eV. A discussion of the periodic trends, summaries of previous work, and comparisons to isoelectronic species is also provided.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Annie S Knapp
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | | | - Andrew Sevy
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Jason J Sorensen
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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4
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Lucci E, Giarrusso S, Gigli G, Ciccioli A. The AuSc, AuTi, and AuFe molecules: determination of the bond energies by Knudsen Effusion Mass Spectrometry experiments combined with ab initio calculations. J Chem Phys 2022; 157:084303. [DOI: 10.1063/5.0094621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The AuTi gaseous molecule was for the first time identified in vapors produced at high temperature from a gold-titanium alloy. The homogeneous equilibria AuTi(g) = Au(g) + Ti(g) (direct dissociation) and AuTi(g) + Au(g) = Au2(g) + Ti(g) (isomolecular exchange) were studied by Knudsen Effusion Mass Spectrometry (KEMS) in the temperature range 2111 -2229 K. The so determined equilibrium constants were treated by the "third-law method" of thermodynamic analysis, integrated with theoretical calculations, and the dissociation energy at 0 K was derived as (AuTi) = 241.0 {plus minus} 5.2 kJ/mol. A similar investigation was carried out for the AuSc and AuFe species, whose dissociation energies were previously reported with large uncertainties. The direct dissociation and the isomolecular exchange with the Au2 dimer were studied in the 1969-2274 and 1842-2092 K ranges for AuSc and AuFe, respectively, and the dissociation energies derived as (AuSc) = 240.4 {plus minus} 6.0 and (AuFe) = 186.2 {plus minus} 4.2 kJ/mol. The experimental bond energies are compared with those calculated here by CCSD(T) with the correlation-consistent basis sets cc-pVXZ(-PP) and cc-pwCVXZ(-PP) (with X = T,Q,5), also in the limit of complete basis set, and with those from CASSCF-MRCI calculations, recently available in the literature. The stronger bond of AuTi compared to AuFe parallels the trend observed in monochlorides. This analogy is shown to be more generally observed in the AuM and MCl diatomic series (with M = first-row transition metal), in accordance with a picture of "pseudo-halogen" bonding behaviour of gold.
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Affiliation(s)
- Elena Lucci
- University of Rome La Sapienza Department of Chemistry, Italy
| | - Sara Giarrusso
- Chemistry and Biochemistry, University of California Merced, United States of America
| | - Guido Gigli
- University of Rome La Sapienza Department of Chemistry, Italy
| | - Andrea Ciccioli
- Dipartimento di Chimica, University of Rome La Sapienza Department of Chemistry, Italy
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5
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S Almeida NM, Melin TRL, North SC, Welch BK, Wilson AK. Ab initio composite strategies and multireference approaches for lanthanide sulfides and selenides. J Chem Phys 2022; 157:024105. [PMID: 35840393 DOI: 10.1063/5.0094367] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The f-block ab initio correlation consistent composite approach was used to predict the dissociation energies of lanthanide sulfides and selenides. Geometry optimizations were carried out using density functional theory and coupled cluster singles, doubles, and perturbative triples with one- and two-component Hamiltonians. For the two-component calculations, relativistic effects were accounted for by utilizing a third-order Douglas-Kroll-Hess Hamiltonian. Spin-orbit coupling was addressed with the Breit-Pauli Hamiltonian within a multireference configuration interaction approach. The state averaged complete active space self-consistent field wavefunctions obtained for the spin-orbit coupling energies were used to assign the ground states of diatomics, and several diagnostics were used to ascertain the multireference character of the molecules.
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Affiliation(s)
- Nuno M S Almeida
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, USA
| | - Timothé R L Melin
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, USA
| | - Sasha C North
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, USA
| | - Bradley K Welch
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, USA
| | - Angela K Wilson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48864, USA
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6
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Merriles DM, Tomchak KH, Nielson C, Morse MD. Early Transition Metals Strengthen the B 2 Bond in MB 2 Complexes. J Am Chem Soc 2022; 144:7557-7561. [PMID: 35439416 DOI: 10.1021/jacs.1c13709] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bond dissociation energies of early transition metal diborides (M-B2, M = Sc, Ti, V, Y, Mo) have been measured by observation of the sharp onset of predissociation in a highly congested spectrum. Density functional and CCSD(T) ab initio calculations, extrapolated to the complete basis set limit, have been used to examine the electronic structure of these species. The computations demonstrate the formation of bonding orbitals between the metal d orbitals and the 1πu bonding orbitals of B2, leading to the transfer of metallic electron density into the bonding 1πu orbitals, strengthening both the M-B and B-B bonds in the molecule. This runs counter to most metal-ligand π interactions, where electron density is generally transferred into π antibonding orbitals of the ligand.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Kimberly H Tomchak
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Christopher Nielson
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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7
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Tzeli D, Karapetsas I, Merriles DM, Ewigleben JC, Morse MD. Molybdenum-Sulfur Bond: Electronic Structure of Low-Lying States of MoS. J Phys Chem A 2022; 126:1168-1181. [PMID: 35147425 DOI: 10.1021/acs.jpca.1c10672] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The molybdenum-sulfur bond plays an important role in many processes such as nitrogen-fixation, and it is found as a building block in layered materials such as MoS2, known for its various shapes and morphologies. Here, we present an accurate theoretical and experimental investigation of the chemical bonding and the electronic structure of 20 low-lying states of the MoS molecule. Multireference and coupled cluster methodologies, namely, MRCISD, MRCISD + Q, RCCSD(T), and RCCSD[T], were employed in conjunction with basis sets up to aug-cc-pwCV5Z-PP/aug-cc-pwCV5Z for the study of these states. We note the significance of including the inner 4s24p6 electrons of Mo and 2s22p6 of S in the correlated space to obtain accurate results. Experimentally, the predissociation threshold of MoS was measured using resonant two-photon ionization spectroscopy, allowing for a precise measurement of the bond dissociation energy. Our extrapolated computational D0 value for the ground state is 3.936 eV, in excellent agreement with our experimental measurement of 3.932 ± 0.004 eV. The largest calculated adiabatic D0 (5.74 eV) and the largest dipole moment (6.50 D) were found for the 5Σ+ state, where a triple bond is formed. Finally, the connection of the chemical bonding of the isolated MoS species to the relevant solid, MoS2, is emphasized. The low-lying septet states of the diatomic molecule are involved in the material as a building block, explaining the stability and the variety of the shapes and morphologies of the material.
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Affiliation(s)
- Demeter Tzeli
- Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 15784, Greece.,Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Ioannis Karapetsas
- Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 15784, Greece
| | - Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Joshua C Ewigleben
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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8
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Hou G, Yang T, Li M, Vanbuel J, Lushchikova OV, Ferrari P, Bakker JM, Janssens E. Water Splitting by C
60
‐Supported Vanadium Single Atoms. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202112398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gao‐Lei Hou
- Quantum Solid-State Physics Department of Physics and Astronomy KU Leuven Celestijnenlaan 200D 3001 Leuven Belgium
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Tao Yang
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Mengyang Li
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Jan Vanbuel
- Quantum Solid-State Physics Department of Physics and Astronomy KU Leuven Celestijnenlaan 200D 3001 Leuven Belgium
| | - Olga V. Lushchikova
- Radboud University Institute for Molecules and Materials FELIX Laboratory Toernooiveld 7 6525 ED Nijmegen The Netherlands
| | - Piero Ferrari
- Quantum Solid-State Physics Department of Physics and Astronomy KU Leuven Celestijnenlaan 200D 3001 Leuven Belgium
| | - Joost M. Bakker
- Radboud University Institute for Molecules and Materials FELIX Laboratory Toernooiveld 7 6525 ED Nijmegen The Netherlands
| | - Ewald Janssens
- Quantum Solid-State Physics Department of Physics and Astronomy KU Leuven Celestijnenlaan 200D 3001 Leuven Belgium
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9
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Merriles DM, Tomchak KH, Ewigleben JC, Morse MD. Predissociation measurements of the bond dissociation energies of EuO, TmO, and YbO. J Chem Phys 2021; 155:144303. [PMID: 34654298 DOI: 10.1063/5.0068543] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The observation of a sharp predissociation threshold in the resonant two-photon ionization spectra of EuO, TmO, and YbO has been used to measure the bond dissociation energies of these species. The resulting values, D0(EuO) = 4.922(3) eV, D0(TmO) = 5.242(6) eV, and D0(YbO) = 4.083(3) eV, are in good agreement with previous values but are much more precise. In addition, the ionization energy of TmO was measured by the observation of a threshold for one-color two-photon ionization of this species, resulting in IE(TmO) = 6.56(2) eV. The observation of a sharp predissociation threshold for EuO was initially surprising because the half-filled 4f7 subshell of Eu in its ground state generates fewer potential energy curves than in the other molecules we have studied by this method. The observation of a sharp predissociation threshold in YbO was even more surprising, given that the ground state of Yb is nondegenerate (4f146s2, 1Sg) and the lowest excited state of Yb is over 2 eV higher in energy. It is suggested that these molecules possess a high density of electronic states at the energy of the ground separated atom limit because ion-pair states drop below the ground limit, providing a sufficient electronic state density to allow predissociation to set in at the thermochemical threshold.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Kimberly H Tomchak
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Joshua C Ewigleben
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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10
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Hou GL, Yang T, Li M, Vanbuel J, Lushchikova OV, Ferrari P, Bakker JM, Janssens E. Water Splitting by C 60 -Supported Vanadium Single Atoms. Angew Chem Int Ed Engl 2021; 60:27095-27101. [PMID: 34610202 DOI: 10.1002/anie.202112398] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Indexed: 12/28/2022]
Abstract
Water splitting is an important source of hydrogen, a promising future carrier for clean and renewable energy. A detailed understanding of the mechanisms of water splitting, catalyzed by supported metal atoms or nanoparticles, is essential to improve the design of efficient catalysts. Here, we report an infrared spectroscopic study of such a water splitting process, assisted by a C60 supported vanadium atom, C60 V+ +H2 O→C60 VO+ +H2 . We probe both the entrance channel complex C60 V+ (H2 O) and the end product C60 VO+ , and observe the formation of H2 as a result from resonant infrared absorption. Density functional theory calculations exploring the detailed reaction pathway reveal that a quintet-to-triplet spin crossing facilitates the water splitting reaction by C60 -supported V+ , whereas this reaction is kinetically hindered on the isolated V+ ion by a high energy barrier. The C60 support has an important role in lowering the reaction barrier with more than 70 kJ mol-1 due to a large orbital overlap of one water hydrogen atom with one carbon atom of the C60 support. This fundamental insight in the water splitting reaction by a C60 -supported single vanadium atom showcases the importance of supports in single atom catalysts by modifying the reaction potential energy surface.
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Affiliation(s)
- Gao-Lei Hou
- Quantum Solid-State Physics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium.,MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Tao Yang
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Mengyang Li
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Jan Vanbuel
- Quantum Solid-State Physics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
| | - Olga V Lushchikova
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525, ED, Nijmegen, The Netherlands
| | - Piero Ferrari
- Quantum Solid-State Physics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
| | - Joost M Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525, ED, Nijmegen, The Netherlands
| | - Ewald Janssens
- Quantum Solid-State Physics, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium
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11
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Lockwood SP, Chunga T, Metz RB. Bonding, Thermodynamics, and Dissociation Dynamics of NiO + and NiS + Determined by Photofragment Imaging and Theory. J Phys Chem A 2021; 125:7425-7436. [PMID: 34427080 DOI: 10.1021/acs.jpca.1c05405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use photofragment ion imaging and ab initio calculations to determine the bond strength and photodissociation dynamics of the nickel oxide (NiO+) and nickel sulfide (NiS+) cations. NiO+ photodissociates broadly from 20350 to 32000 cm-1, forming ground state products Ni+(2D) + O(3P) below ∼29000 cm-1. Above this energy, Ni+(4F) + O(3P) products become accessible and dominate over the ground state channel. In certain images, product spin-orbit levels are resolved, and spin-orbit propensities are determined. Image anisotropy and the results of MRCI calculations suggest NiO+ photodissociates via a 3 4Σ- ← X 4Σ- transition above the Ni+(4F) threshold and via 3 4Σ-, 2 4Σ-, and/or 2 4Π and 3 4Π excited states below the 4F threshold. The photodissociation spectrum of NiS+ from 19900 to 23200 cm-1 is highly structured, with ∼12 distinct vibronic peaks, each containing underlying substructure. Above 21600 cm-1, the Ni+(2D5/2) + S(3P) and Ni+(2D3/2) + S(3P) product spin-orbit channels compete, with a branching ratio of ∼2:1. At lower energy, Ni+(2D5/2) is formed exclusively, and S(3P2) and S(3P1) spin-orbit channels are resolved. MRCI calculations predict the ground state of NiS+ to be one of two nearly degenerate states, the 1 4Σ- and 1 4Δ. Based on images and spectra, the ground state of NiS+ is assigned as 4Δ7/2, with the 1 4Σ3/2- and 1 4Σ1/2- states 81 ± 30 and 166 ± 50 cm-1 higher in energy, respectively. The majority of the photodissociation spectrum is assigned to transitions from the 1 4Δ state to two overlapping, predissociative excited 4Δ states. Our D0 measurements for NiO+ (D0 = 244.6 ± 2.4 kJ/mol) and NiS+ (D0 = 240.3 ± 1.4 kJ/mol) are more precise and closer to each other than previously reported values. Finally, using a recent measurement of D0(NiS), we derive a more precise value for IE (NiS): 8.80 ± 0.02 eV (849 ± 1.7 kJ/mol).
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Affiliation(s)
- Schuyler P Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Tala Chunga
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Ricardo B Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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12
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Sorensen JJ, Tieu E, Morse MD. Bond dissociation energies of lanthanide sulfides and selenides. J Chem Phys 2021; 154:124307. [PMID: 33810674 DOI: 10.1063/5.0042695] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Resonant two-photon ionization spectroscopy has been employed to observe sharp predissociation thresholds in the spectra of the lanthanide sulfides and selenides for the 4f metals Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. As these molecules possess a large density of electronic states near the ground separated atom limit, these predissociation thresholds are argued to coincide with the true 0 K bond dissociation energies (BDEs). This is because spin-orbit and nonadiabatic couplings among these states allow the molecules to predissociate rapidly when the BDE is reached or exceeded. The measured BDEs, in eV, are as follows: 5.230(3) (PrS), 4.820(3) (NdS), 4.011(17) (SmS), 3.811(8) (EuS), 5.282(5) (GdS), 5.292(3) (TbS), 4.298(3) (DyS), 4.251(3) (HoS), 4.262(3) (ErS), 5.189(3) (LuS), 4.496(3) (PrSe), 4.099(3) (NdSe), 3.495(17) (SmSe), 3.319(3) (EuSe), 4.606(3) (GdSe), 4.600(6) (TbSe), 3.602(3) (DySe), 3.562(3) (HoSe), 3.587(3) (ErSe), and 4.599(6) (LuSe). Through the use of thermochemical cycles, the 0 K gaseous heat of formation, ΔfH0K ○, is reported for each molecule. A threshold corresponding to the onset of two-photon ionization in EuSe was also observed, providing the ionization energy of EuSe as 6.483(10) eV. Through a thermochemical cycle and the above reported BDE of the neutral EuSe molecule, the BDE for the Eu+-Se cation was also determined as D0(Eu+-Se) = 2.506(10) eV. Bonding trends of the lanthanide sulfides and selenides are discussed. Our previous observation that the transition metal sulfides are 15.6% more strongly bound than the corresponding selenides continues to hold true for the lanthanides as well.
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Affiliation(s)
- Jason J Sorensen
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Erick Tieu
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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13
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Köckert H, Gentleman AS, Pickering J, Mackenzie SR. A velocity map imaging study of multiphoton photodissociation and photoionisation dynamics in niobium oxide, NbO. Mol Phys 2021. [DOI: 10.1080/00268976.2020.1821924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Hansjochen Köckert
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, UK
| | - Alexander S. Gentleman
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, UK
| | - Jack Pickering
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, UK
| | - Stuart R. Mackenzie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford, UK
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14
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Sorensen JJ, Tieu E, Sevy A, Merriles DM, Nielson C, Ewigleben JC, Morse MD. Bond dissociation energies of transition metal oxides: CrO, MoO, RuO, and RhO. J Chem Phys 2020; 153:074303. [PMID: 32828096 DOI: 10.1063/5.0021052] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Through the use of resonant two-photon ionization spectroscopy, sharp predissociation thresholds have been identified in the spectra of CrO, MoO, RuO, and RhO. Similar thresholds have previously been used to measure the bond dissociation energies (BDEs) of many molecules that have a high density of vibronic states at the ground separated atom limit. A high density of states allows precise measurement of the BDE by facilitating prompt dissociation to ground state atoms when the BDE is exceeded. However, the number of states required for prompt predissociation at the thermochemical threshold is not well defined and undoubtedly varies from molecule to molecule. The ground separated atom limit generates 315 states for RuO, 252 states for RhO, and 63 states for CrO and MoO. Although comparatively few states derive from this limit for CrO and MoO, the observation of sharp predissociation thresholds for all four molecules nevertheless allows BDEs to be assigned as 4.863(3) eV (RuO), 4.121(3) eV (RhO), 4.649(5) eV (CrO), and 5.414(19) eV (MoO). Thermochemical cycles are used to derive the enthalpies of formation of the gaseous metal oxides and to obtain IE(RuO) = 8.41(5) eV, IE(RhO) = 8.56(6) eV, D0(Ru-O-) = 4.24(2) eV, D0(Cr-O-) = 4.409(8) eV, and D0(Mo-O-) = 5.243(20) eV. The mechanisms leading to prompt predissociation at threshold in the cases of CrO and MoO are discussed. Also presented is a discussion of the bonding trends for the transition metal oxides, which are compared to the previously measured transition metal sulfides.
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Affiliation(s)
- Jason J Sorensen
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Erick Tieu
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Andrew Sevy
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Christopher Nielson
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Joshua C Ewigleben
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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