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The kinetic energy dependent reactions of Re + with SO 2 were studied with guided ion beam tandem mass spectrometry. ReO + , ReO 2 + , and OReS + species were observed as products, all in endothermic reactions. Modeling of the kinetic energy dependent cross sections yields 0 K bond dissociation energies (BDEs, in eV) of 4.78 ± 0.06 (Re + –O), 5.75 ± 0.02 (Re + –O 2 ), and 4.35 ± 0.14 (Re + –SO). The latter two values can be combined with other information to derive the additional values 6.05 ± 0.05 (ORe + –O) and 4.89 ± 0.19 (ORe + –S). BDEs of ReO + and ReO 2 + agree with literature values whereas the values for OReS + are the first measurements. The former result is obtained even though formation of ground state ReO + is spin-forbidden. Quantum mechanical calculations at the B3LYP level of theory with a def2-TZVPPD basis set yield results that agree reasonably well with experimental values. Additional calculations at the BP86 and CCSD(T) levels of theory using def2-QZVPPD and aug-cc-pVxZ (x = T, Q, and 5) basis sets were performed to compare thermochemistry with experiment to determine that ReO 2 + rather than the isobaric ReS + is formed. Product ground states are 3 Δ 3 (ReO + ), 3 B 1 (OReO + ), 5 Π −1 (ReS + ), and 3 A′′(OReS + ) after including empirical spin–orbit corrections, which means that formation of ground state products is spin-forbidden for all three product channels. The potential energy surfaces for the ReSO 2 + system were also explored at the B3LYP/def2-TZVPPD level and exhibited no barriers in excess of the endothermicities for all products. BDEs for rhenium oxide and sulfide diatomics and triatomics are compared and discussed. The present result for formation of ReO + is compared to that for formation of ReO + in the reactions of Re + + O 2 and CO, where the former system exhibited interesting dual cross section features. Results are consistent with the hypothesis that the distinction of in-plane and out-of-plane C S symmetry in the triatomic systems might be the explanation for the two endothermic features observed in the Re + + O 2 reaction.
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Thermochemical properties of small rhenium molecules: ReC, ReN, ReO, ReS, and ReC2
The rhenium-containing molecules ReC, ReN, ReO, ReS, and ReC2 have been investigated using a pulsed laser ablation supersonic beam molecular source in resonant two-photon ionization experiments with time-of-flight mass spectrometric detection. Sharp predissociation thresholds have been observed, allowing precise bond dissociation energies (BDEs) to be measured as D0(ReC) = 5.731(3) eV, D0(ReN) = 5.635(3) eV, D0(ReO) = 5.510(3) eV, D0(ReS) = 3.947(3) eV, and D0(Re–C2) = 5.359(3) eV. The threshold for two-photon ionization was also measured for ReC, ReN, and ReO, providing ionization energies (IEs) of IE(ReC) = 8.425(12) eV, IE(ReN) = 8.193(20) eV, and IE(ReO) = 8.561(11) eV. These are the first measurements of these thermochemical quantities to be reported in the literature. The combination of BDEs and IEs allowed the BDEs of the cations ReC+, ReN+, and ReO+ to be determined via a thermochemical cycle as D0(Re+-C) = 5.140(12) eV, D0(Re+-N) = 5.275(20) eV, and D0(Re+-O) = 4.783(11) eV. In addition, computations of these thermochemical values were performed using density functional theory [B3LYP/aug-cc-pVQZ(-PP)] to determine the ground states and their geometric parameters. These were further studied at the CCSD(T) level with extrapolation to the complete basis set limit using aug-cc-pVXZ(-PP) basis sets (X = 3, 4, 5) to obtain computational values of the BDEs and IEs as well. The high-level super correlation consistent composite approach (s-ccCA) was also utilized, providing an additional approach for the prediction of thermochemical values. The electronic structure of the molecules is discussed, along with the periodic trends as the ligand is varied.
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- Award ID(s):
- 2305293
- PAR ID:
- 10648119
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 163
- Issue:
- 19
- ISSN:
- 0021-9606
- Subject(s) / Keyword(s):
- Bond dissociation energies rhenium carbide rhenium nitride rhenium oxide rhenium sulfide rhenium dicarbide ionization energies
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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