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Title: Bond energies of ThO + and ThC + : A guided ion beam and quantum chemical investigation of the reactions of thorium cation with O 2 and CO

Kinetic energy dependent reactions of Th + with O 2 and CO are studied using a guided ion beam tandem mass spectrometer. The formation of ThO + in the reaction of Th + with O 2 is observed to be exothermic and barrierless with a reaction efficiency at low energies of k/k LGS = 1.21 ± 0.24 similar to the efficiency observed in ion cyclotron resonance experiments. Formation of ThO + and ThC + in the reaction of Th + with CO is endothermic in both cases. The kinetic energy dependent cross sections for formation of these product ions were evaluated to determine 0 K bond dissociation energies (BDEs) of D 0(Th +–O) = 8.57 ± 0.14 eV and D 0(Th +–C) = 4.82 ± 0.29 eV. The present value of D 0(Th +–O) is within experimental uncertainty of previously reported experimental values, whereas this is the first report of D 0(Th +–C). Both BDEs are observed to be larger than those of their transition metal congeners, TiL +, ZrL +, and HfL + (L = O and C), believed to be a result of lanthanide contraction. Additionally, the reactions were explored by quantum chemical calculations, including a full Feller-Peterson-Dixonmore » composite approach with correlation contributions up to coupled-cluster singles and doubles with iterative triples and quadruples (CCSDTQ) for ThC, ThC +, ThO, and ThO +, as well as more approximate CCSD with perturbative (triples) [CCSD(T)] calculations where a semi-empirical model was used to estimate spin-orbit energy contributions. In conclusion, the ThO + BDE is compared to other actinide (An) oxide cation BDEs and a simple model utilizing An+ promotion energies to the reactive state is used to estimate AnO + and AnC + BDEs. For AnO +, this model yields predictions that are typically within experimental uncertainty and performs better than density functional theory calculations presented previously.« less
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [2] ; ORCiD logo [2]
  1. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Chemistry
  2. Washington State Univ., Pullman, WA (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0012249; FG02-12ER16329
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 144; Journal Issue: 18; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Utah, Salt Lake City, UT (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
OSTI Identifier:
1471100
Alternate Identifier(s):
OSTI ID: 1253063