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Tomchak KH, Sorensen JJ, Tieu E, Morse MD. Predissociation-based measurements of bond dissociation energies: US2, OUS, and USe. J Chem Phys 2024; 161:044306. [PMID: 39041877 DOI: 10.1063/5.0220813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 07/05/2024] [Indexed: 07/24/2024] Open
Abstract
The uranium-containing molecules US2, OUS, and USe have been investigated using a pulsed laser ablation supersonic beam molecular source with time-of-flight mass spectrometric detection. Spectra have been recorded using the resonant two-photon ionization method over the spectroscopic range from 277 to 238 nm. These species have a myriad of excited electronic states in this spectroscopic region, leading to spectra that are highly congested and appear quasicontinuous. Sharp predissociation thresholds are observed, allowing precise bond dissociation energies to be measured. In the case of the triatomic molecules, it was necessary to use one laser for excitation and a delayed laser for ionization in order to observe a sharp predissociation threshold that allowed a precise bond dissociation energy to be measured. The resulting thermochemical values are D0(SU-S) = 4.910 ± 0.003 eV, D0(OU-S) = 5.035 ± 0.004 eV, and D0(USe) = 4.609 ± 0.009 eV. These results provide the first measurement of D0(USe) and reduce the error limits in the previous values of D0(SU-S) and D0(OU-S) by a factor of more than 70.
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Affiliation(s)
- Kimberly H Tomchak
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
| | - Jason J Sorensen
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
| | - Erick Tieu
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
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Merriles DM, London A, Tieu E, Nielson C, Morse MD. Probing the Chemical Bond between Lanthanides and Carbon: CeC, PrC, NdC, LuC, and TmC 2. Inorg Chem 2023. [PMID: 37285469 DOI: 10.1021/acs.inorgchem.3c01042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Resonant two-photon ionization experiments have been conducted to probe the bond dissociation energy (BDE) of the lanthanide-carbon bond, allowing the BDEs of CeC, PrC, NdC, LuC, and Tm-C2 to be measured to high precision. Values of D0(CeC) = 4.893(3) eV, D0(PrC) = 4.052(3) eV, D0(NdC) = 3.596(3) eV, D0(LuC) = 3.685(4) eV, and D0(Tm-C2) = 4.797(6) eV are obtained. Additionally, the adiabatic ionization energy of LuC was measured, giving IE(LuC) = 7.05(3) eV. The electronic structure of these species, along with the previously measured LaC, has been further investigated using quantum chemical calculations. Despite LaC, CeC, PrC, and NdC having ground electronic configurations that differ only in the number of 4f electrons present and have virtually identical bond orders, bond lengths, fundamental stretching frequencies, and metallic oxidation states, a peculiar 1.30 eV range in bond dissociation energies exists for these molecules. A natural bond orbital analysis shows that the metal atoms in these molecules have a natural charge of +1 with a 5d2 4fn 6s0 configuration while the carbon atom has a natural charge of -1 and a 2p3 configuration. The diabatic bond dissociation energies, calculated with respect to the lowest energy level of this separated ion configuration, show a greatly reduced energy range of 0.32 eV, with the diabatic BDE decreasing as the amount of 4f character in the σ-bond increases. Thus, the wide range of measured BDEs for these molecules is a consequence of the variation in atomic promotion energies at the separated ion limit. TmC2 has a smaller BDE than the other LnC2 molecules, due to the tiny amount of 5d participation in the valence molecular orbitals.
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Affiliation(s)
- Dakota M Merriles
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Anthony London
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Erick Tieu
- 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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Chen D, Zhao Z, Chen G, Li T, Chen J, Ye Z, Lu J. Metal selenides for energy storage and conversion: A comprehensive review. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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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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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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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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Merriles DM, Nielson C, Tieu E, Morse MD. Chemical Bonding and Electronic Structure of the Early Transition Metal Borides: ScB, TiB, VB, YB, ZrB, NbB, LaB, HfB, TaB, and WB. J Phys Chem A 2021; 125:4420-4434. [PMID: 34003640 DOI: 10.1021/acs.jpca.1c02886] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The predissociation thresholds of the early transition metal boride diatomics (MB, M = Sc, Ti, V, Y, Zr, Nb, La, Hf, Ta, W) have been measured using resonant two-photon ionization (R2PI) spectroscopy, allowing for a precise assignment of the bond dissociation energy (BDE). No previous experimental measurements of the BDE exist in the literature for these species. Owing to the high density of electronic states arising from the ground and low-lying separated atom limits in these open d-subshell species, a congested spectrum of vibronic transitions is observed as the energy of the ground separated atom limit is approached. Nonadiabatic and spin-orbit interactions among these states, however, provide a pathway for rapid predissociation as soon as the ground separated atom limit is reached, leading to a sharp decrease in signal to background levels when this limit is reached. Accordingly, the BDEs of the early transition metal borides have been assigned as D0(ScB) 1.72(6) eV, D0(TiB) 1.956(16) eV, D0(VB) 2.150(16) eV, D0(YB) 2.057(3) eV, D0(ZrB) 2.573(5) eV, D0(NbB) 2.989(12) eV, D0(LaB) 2.086(18) eV, D0(HfB) 2.593(3) eV, D0(TaB) 2.700(3) eV, and D0(WB) 2.730(4) eV. Additional insight into the chemical bonding and electronic structures of these species has been achieved by quantum chemical calculations.
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Affiliation(s)
- Dakota M Merriles
- 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
| | - Erick Tieu
- 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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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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Liu Z, Pan J, Zhang YF, Du S. Half-auxetic effect and ferroelasticity in a two-dimensional monolayer TiSe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:144002. [PMID: 33461183 DOI: 10.1088/1361-648x/abdcea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) materials with both auxetic effect and ferroelasticity are rare, however, have great application potential in next generation microelectromechanical and nanoelectronic devices. Here, we report the findings of an extraordinary combination half-auxetic effect and ferroelasticity in a single p2mm-type TiSe monolayer by performing first-principles calculations. The unique half-auxetic effect, namely the material expand laterally under both uniaxial tensile strain, and compressive strain, is reported and explained by considering both the nearest and the next-nearest interactions. The ferroelasticity is stemming from the degeneracy breaking of the3d-orbitals of Ti atoms in a distorted tetrahedron crystal field, or the so-called Jahn-Teller effect. The results provide a guideline for the future design of novel 2D multiple functional materials at the nanoscale.
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Affiliation(s)
- Ziyuan Liu
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Jinbo Pan
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yan-Fang Zhang
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shixuan Du
- Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan 523808, People's Republic of China
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10
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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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11
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Merriles DM, Sevy A, Nielson C, Morse MD. The bond dissociation energy of VO measured by resonant three-photon ionization spectroscopy. J Chem Phys 2020; 153:024303. [PMID: 32668947 DOI: 10.1063/5.0014006] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The predissociation threshold of VO has been measured using resonant three-photon ionization (R3PI) spectroscopy. Given the high density of electronic states in the molecule, it is argued that the molecule dissociates rapidly as soon as the thermochemical bond dissociation energy (BDE) is exceeded, allowing the measured predissociation threshold to be assigned as the BDE. This is the first time a BDE has been measured using the R3PI method. The first photon is provided by an optical parametric oscillator (OPO) laser that promotes VO into a high-energy, discrete vibronic state. A tunable dye laser then excites the molecule further to a resonant state close to the dissociation limit where there is a quasi-continuum of states. A second photon from the same dye laser pulse ionizes the molecule, generating VO+ ions. The dye laser is then scanned to higher energies, and when the energy of one OPO photon plus one dye photon exceeds the BDE, the molecule dissociates before another dye photon can be absorbed to induce ionization. The combined photon energy at the sharp drop in the ion signal is assigned as the BDE. The experiment has been repeated using four different intermediate states, all yielding the same BDE, D0(VO) = 6.545(2) eV. Using thermochemical cycles, a revised value for the BDE of cationic VO is obtained, D0(V+-O) = 6.053(2) eV. The 0 K enthalpy of formation for VO(g) is also derived as ΔfH0K 0VO(g) = 128.6(1.0) kJ mol-1. Previous spectroscopic and thermochemical studies of VO are reviewed.
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Affiliation(s)
- Dakota M Merriles
- 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
| | - Christopher Nielson
- 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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12
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Sorensen JJ, Tieu E, Morse MD. Bond dissociation energies of the diatomic late transition metal sulfides: RuS, OsS, CoS, RhS, IrS, and PtS. J Chem Phys 2020; 152:244305. [PMID: 32610999 DOI: 10.1063/5.0011754] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The spectra of RuS, OsS, CoS, RhS, IrS, and PtS have been recorded near their respective bond dissociation energies using resonant two-photon ionization spectroscopy. The spectra display an abrupt drop to baseline when the bond dissociation energy (BDE) is exceeded. It is argued that spin-orbit and nonadiabatic interactions among the myriad of states that result from the ground and low-lying separated atom limits cause the molecules to predissociate rapidly as soon as the ground separated atom limit is exceeded in energy. Thus, the observed sharp predissociation thresholds are assigned as the 0 K BDEs of the molecules. With this assumption, the BDEs are assigned as follows: 4.071(8) eV (RuS), 4.277(3) eV (OsS), 3.467(5) eV (CoS), 3.611(3) eV (RhS), 4.110(3) eV (IrS), and 4.144(8) eV (PtS). Using thermochemical cycles, the gas-phase enthalpies of formation at 0 K, ΔfH0 K°, were calculated to be 531.8(4.3) kJ mol-1 (RuS), 651.2(6.3) kJ mol-1 (OsS), 365.3(2.2) kJ mol-1 (CoS), 481.5(2.1) kJ mol-1 (RhS), 546.7(6.3) kJ mol-1 (IrS), and 438.9(1.5) kJ mol-1 (PtS). The ionization energies of RuS, CoS, and RhS were also calculated using data on the BDEs of the associated cations and were found to be 8.39(10) eV (RuS), 8.40(9) eV (CoS), and 8.46(12) eV (RhS). Combining these data with predissociation measurements of other transition metal sulfide BDEs, the periodic trends in the transition metal sulfide BDEs are discussed and the BDEs of the transition metal sulfides are compared to those of the corresponding selenides. The BDEs of the sulfides are found to be 15.4% greater than those of the corresponding 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
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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13
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Sorensen JJ, Tieu E, Nielson C, Sevy A, Tomchak KH, Morse MD. Bond dissociation energies of diatomic transition metal sulfides: ScS, YS, TiS, ZrS, HfS, NbS, and TaS. J Chem Phys 2020; 152:194307. [PMID: 33687227 DOI: 10.1063/5.0009132] [Citation(s) in RCA: 12] [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 early transition metal diatomic sulfides, MS, M = Sc, Y, Ti, Zr, Hf, Nb, and Ta, have been investigated using resonant two-photon ionization spectroscopy in the vicinity of their bond dissociation energies (BDEs). Due to the high density of vibronic states in this energy range, the molecular spectra appear quasicontinuous, and when the excitation energy exceeds the ground separated atom limit, excited state decay by dissociation becomes possible. The dissociation process typically occurs so rapidly that the molecule falls apart before a second photon can be absorbed to ionize the species, leading to a sharp drop in ion signal, which is identified as the 0 K BDE. The observed predissociation thresholds yield BDEs of 4.852(10) eV (ScS), 5.391(3) eV (YS), 4.690(4) eV (TiS), 5.660(4) eV (ZrS), 5.780(20) eV (HfS), 5.572(3) eV (NbS), and 5.542(3) eV (TaS). Utilizing thermochemical cycles, the enthalpies of formation, ΔfH0K o(g), of 182.7(4.3) kJ mol-1 (ScS), 178.3(4.2) kJ mol-1 (YS), 293.1(16.7) kJ mol-1 (TiS), 337.3(8.4) kJ mol-1 (ZrS), 335.0(6.6) kJ mol-1 (HfS), 467.0(8.0) kJ mol-1 (NbS), and 521.5(2.1) kJ mol-1 (TaS) are obtained. Another thermochemical cycle has been used to combine the previously measured M+-S BDEs with the M-S BDEs and atomic ionization energies to obtain the MS ionization energies of 6.44(5) eV (ScS), 6.12(8) eV (YS), 6.78(7) eV (TiS), 6.60(10) eV (ZrS), and 6.88(9) eV (NbS). Using this same cycle, we obtain D0(Hf+-S) = 4.926(20) eV. The bonding trends of the early transition metal sulfides, along with the corresponding selenides, are discussed.
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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
| | - Christopher Nielson
- 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
| | - Kimberly H Tomchak
- 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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14
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Sorensen JJ, Tieu E, Morse MD. Bond dissociation energies of diatomic transition metal selenides: ScSe, YSe, RuSe, OsSe, CoSe, RhSe, IrSe, and PtSe. J Chem Phys 2020; 152:124305. [PMID: 32241137 DOI: 10.1063/5.0003136] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The diatomic transition metal selenides, MSe (M = Sc, Y, Ru, Os, Co, Rh, Ir, and Pt), were studied by resonant two-photon ionization spectroscopy near their respective bond dissociation energies. As these molecules exhibit high densities of vibronic states near their dissociation limits, the spectra typically appear quasicontinuously at these energies. Spin-orbit and nonadiabatic couplings among the multitudes of potential curves allow predissociation to occur on a rapid timescale when the molecule is excited to states lying above the ground separated atom limit. This dissociation process occurs so rapidly that the molecules are dissociated before they can be ionized by the absorption of a second photon. This results in an abrupt drop in the ion signal that is assigned as the 0 K bond dissociation energy for the molecule, giving bond dissociation energies of 4.152(3) eV (ScSe), 4.723(3) eV (YSe), 3.482(3) eV (RuSe), 3.613(3) eV (OsSe), 2.971(6) eV (CoSe), 3.039(9) eV (RhSe), 3.591(3) eV (IrSe), and 3.790(31) eV (PtSe). The enthalpies of formation, ΔfH0K° (g), for each diatomic metal selenide were calculated using thermochemical cycles, yielding ΔfH0K° (g) values of 210.9(4.5) kJ mol-1 (ScSe), 203.5(4.5) kJ mol-1 (YSe), 549.2(4.5) kJ mol-1 (RuSe), 675.9(6.5) kJ mol-1 (OsSe), 373.9(2.6) kJ mol-1 (CoSe), 497.4(2.7) kJ mol-1 (RhSe), 557.4(6.5) kJ mol-1 (IrSe), and 433.7(3.6) kJ mol-1 (PtSe). Utilizing a thermochemical cycle, the ionization energy for ScSe is estimated to be about 7.07 eV. The bonding trends of the transition metal selenides are discussed.
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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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15
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Merriles DM, Tieu E, Morse MD. Bond dissociation energies of FeB, CoB, NiB, RuB, RhB, OsB, IrB, and PtB. J Chem Phys 2019; 151:044302. [DOI: 10.1063/1.5113511] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dakota M. Merriles
- 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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16
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Sevy A, Merriles DM, Wentz RS, Morse MD. Bond dissociation energies of ScSi, YSi, LaSi, ScC, YC, LaC, CoC, and YCH. J Chem Phys 2019; 151:024302. [PMID: 31301702 DOI: 10.1063/1.5098330] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Predissociation thresholds of the ScSi, YSi, LaSi, ScC, YC, LaC, CoC, and YCH molecules have been measured using resonant two-photon ionization spectroscopy. It is argued that the dense manifold of electronic states present in these molecules causes prompt dissociation when the bond dissociation energy (BDE) is exceeded, allowing their respective predissociation thresholds to provide precise values of their bond energies. The BDEs were measured as 2.015(3) eV (ScSi), 2.450(2) eV (YSi), 2.891(5) eV (LaSi), 3.042(10) eV (ScC), 3.420(3) eV (YC), 4.718(4) eV (LaC), 3.899(13) eV (CoC), and 4.102(3) eV (Y-CH). Using thermochemical cycles, the enthalpies of formation, ΔfH0K°(g), were calculated as 627.4(9.0) kJ mol-1 (ScSi), 633.1(9.0) kJ mol-1 (YSi), 598.1(9.0) kJ mol-1 (LaSi), 793.8(4.3) kJ mol-1 (ScC), 805.0(4.2) kJ mol-1 (YC), 687.3(4.2) kJ mol-1 (LaC), 760.1(2.5) kJ mol-1 (CoC), and 620.8(4.2) kJ mol-1 (YCH). Using data for the BDEs of the corresponding cations allows ionization energies to be obtained through thermochemical cycles as 6.07(11) eV (ScSi), 6.15(13) eV (YSi), 5.60(10) eV (LaSi), 6.26(6) eV (ScC), 6.73(12) or 5.72(11) eV [YC, depending on the value of D0(Y+-C) employed], and 5.88(35) eV (LaC). Additionally, a new value of D0(Co+-C) = 4.045(13) eV was obtained based on the present work and the previously determined ionization energy of CoC. An ionization onset threshold allowed the measurement of the LaSi ionization energy as 5.607(10) eV, in excellent agreement with a prediction based on a thermochemical cycle. Chemical bonding trends are also discussed.
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Affiliation(s)
- 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
| | - Rachel S Wentz
- 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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17
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Abstract
A fundamental need in chemistry is understanding the chemical bond, for which the most quantitative measure is the bond dissociation energy (BDE). While BDEs of chemical bonds formed from the lighter main group elements are generally well-known and readily calculated by modern computational chemistry, chemical bonds involving the transition metals, lanthanides, and actinides remain computationally extremely challenging. This is due to the simultaneous importance of electron correlation, spin-orbit interaction, and other relativistic effects, coupled with the large numbers of low-lying states that are accessible in systems with open d or f subshells. The development of efficient and accurate computational methods for these species is currently a major focus of the field. An obstacle to this effort has been the scarcity of highly precise benchmarks for the BDEs of M-X bonds. For most of the transition metal, lanthanide, or actinide systems, tabulated BDEs of M-X bonds have been determined by Knudsen effusion mass spectrometric measurements of high-temperature equilibria. The measured ion signals are converted to pressures and activities of the species involved in the equilibrium, and the equilibrium constants are then analyzed using a van't Hoff plot or the third-law method to extract the reaction enthalpy, which is extrapolated to 0 K to obtain the BDE. This procedure introduces errors at every step and ultimately leads to BDEs that are typically uncertain by 2-20 kcal mol-1 (0.1-1 eV). A second method in common use employs a thermochemical cycle in which the ionization energies of the MX molecule and M atom are combined with the BDE of the M+-X bond, obtained via guided ion beam mass spectrometry, to yield the BDE of the neutral, M-X. When accurate values of all three components of the cycle are available, this method yields good results-but only rarely are all three values available. We have recently implemented a new method for the precise measurement of BDEs in molecules with large densities of electronic states that is based on the rapid predissociation of these species as soon as the ground separated atom limit is exceeded. When a sharp predissociation threshold is observed, its value directly provides the BDE of the system. With this method, we are able in favorable cases to determine M-X BDEs to an accuracy of ∼0.1 kcal mol-1 (0.004 eV). The method is generally applicable to species that have a high density of states at the ground separated atom limit and has been used to measure the BDEs of more than 50 transition metal-main group MX molecules thus far. In addition, a number of metal-metal BDEs have also been measured with this method. There are good prospects for the extension of the method to polyatomic systems and to lanthanide and actinide-containing molecules. These precise BDE measurements provide chemical trends for the BDEs across the transition metal series, as well as crucial benchmarks for the development of efficient and accurate computational methods for the d- and f-block elements.
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Affiliation(s)
- Michael D. Morse
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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18
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Sevy A, Tieu E, Morse MD. Bond dissociation energies of FeSi, RuSi, OsSi, CoSi, RhSi, IrSi, NiSi, and PtSi. J Chem Phys 2018; 149:174307. [PMID: 30409013 DOI: 10.1063/1.5050934] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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 used to investigate the spectra of the diatomic late transition metal silicides, MSi, M = Fe, Ru, Os, Co, Rh, Ir, Ni, and Pt, in the vicinity of the bond dissociation energy. In these molecules, the density of vibronic states is so large that the spectra appear quasicontinuous in this energy range. When the excitation energy exceeds the ground separated atom limit, however, a new decay process becomes available-molecular dissociation. This occurs so rapidly that the molecule falls apart before it can absorb another photon and be ionized. The result is a sharp drop to the baseline in the ion signal, which we identify as occurring at the thermochemical 0 K bond dissociation energy, D0. On this basis, the measured predissociation thresholds provide D0 = 2.402(3), 4.132(3), 4.516(3), 2.862(3), 4.169(3), 4.952(3), 3.324(3), and 5.325(9) eV for FeSi, RuSi, OsSi, CoSi, RhSi, IrSi, NiSi, and PtSi, respectively. Using thermochemical cycles, the enthalpies of formation of the gaseous MSi molecules are derived as 627(8), 700(10), 799(10), 595(8), 599(8), 636(10), 553(12), and 497(8) kJ/mol for FeSi, RuSi, OsSi, CoSi, RhSi, IrSi, NiSi, and PtSi, respectively. Likewise, combining these results with other data provides the ionization energies of CoSi and NiSi as 7.49(7) and 7.62(7) eV, respectively. Chemical bonding trends among the diatomic transition metal silicides are discussed.
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Affiliation(s)
- Andrew Sevy
- 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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19
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Sevy A, Matthew DJ, Morse MD. Bond dissociation energies of TiC, ZrC, HfC, ThC, NbC, and TaC. J Chem Phys 2018; 149:044306. [DOI: 10.1063/1.5041422] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Andrew Sevy
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Daniel J. Matthew
- 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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20
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Sevy A, Sorensen JJ, Persinger TD, Franchina JA, Johnson EL, Morse MD. Bond dissociation energies of TiSi, ZrSi, HfSi, VSi, NbSi, and TaSi. J Chem Phys 2018; 147:084301. [PMID: 28863527 DOI: 10.1063/1.4986213] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Predissociation thresholds have been observed in the resonant two-photon ionization spectra of TiSi, ZrSi, HfSi, VSi, NbSi, and TaSi. It is argued that because of the high density of electronic states at the ground separated atom limit in these molecules, the predissociation threshold in each case corresponds to the thermochemical bond dissociation energy. The resulting bond dissociation energies are D0(TiSi) = 2.201(3) eV, D0(ZrSi) = 2.950(3) eV, D0(HfSi) = 2.871(3) eV, D0(VSi) = 2.234(3) eV, D0(NbSi) = 3.080(3) eV, and D0(TaSi) = 2.999(3) eV. The enthalpies of formation were also calculated as Δf,0KH°(TiSi(g)) = 705(19) kJ mol-1, Δf,0KH°(ZrSi(g)) = 770(12) kJ mol-1, Δf,0KH°(HfSi(g)) = 787(10) kJ mol-1, Δf,0KH°(VSi(g)) = 743(11) kJ mol-1, Δf,0KH°(NbSi(g)) = 879(11) kJ mol-1, and Δf,0KH°(TaSi(g)) = 938(8) kJ mol-1. Using thermochemical cycles, ionization energies of IE(TiSi) = 6.49(17) eV and IE(VSi) = 6.61(15) eV and bond dissociation energies of the ZrSi- and NbSi- anions, D0(Zr-Si-) ≤ 3.149(15) eV, D0(Zr--Si) ≤ 4.108(20) eV, D0(Nb-Si-) ≤ 3.525(31) eV, and D0(Nb--Si) ≤ 4.017(39) eV, have also been obtained. Calculations on the possible low-lying electronic states of each species are also reported.
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Affiliation(s)
- 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
| | - Thomas D Persinger
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA
| | - Jordan A Franchina
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | - Eric L Johnson
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
| | - Michael D Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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Sevy A, Huffaker RF, Morse MD. Bond Dissociation Energies of Tungsten Molecules: WC, WSi, WS, WSe, and WCl. J Phys Chem A 2017; 121:9446-9457. [DOI: 10.1021/acs.jpca.7b09704] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew Sevy
- Department of Chemistry, University of Utah, Salt Lake
City, Utah 84112, United States
| | - Robert F. Huffaker
- 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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22
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Matthew DJ, Tieu E, Morse MD. Determination of the bond dissociation energies of FeX and NiX (X = C, S, Se). J Chem Phys 2017; 146:144310. [DOI: 10.1063/1.4979679] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J. Matthew
- Department of Chemistry, University of Utah, Salt Lake City, Utah UT 84112, USA
| | - Erick Tieu
- Department of Chemistry, University of Utah, Salt Lake City, Utah UT 84112, USA
| | - Michael D. Morse
- Department of Chemistry, University of Utah, Salt Lake City, Utah UT 84112, USA
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