- Thorium fluorides ThF, ThF2, ThF3, ThF4, ThF3(F2), and ThF5- characterized by infrared spectra in solid argon and electronic structure and vibrational frequency calculations
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Reactions of laser-ablated Th atoms with F2 produce ThF 4 as the major product based on agreement with matrix spectra recorded of the vapor from the solid at 800-850 °C. Weaker higher-frequency bands at (567.2, 564.8), (575.9, 575.1), and (531.0, 528.4) cm-1 in argon are assigned to ThF, ThF2 and ThF3, ThF 3(F2) on the basis of their chemical behavior upon increasing reagent concentrations, annealing, and irradiation, the use of NF3, OF2, and HF as F-atom sources, and a comparison with frequencies calculated at the DFT/B3LYP and CCSD(T) levels with a large segmented + ECP basis set on Th and the aug-cc-pVTZ basis set on F. An additional broader band at 460 cm-1 is assigned to the ThF 5- anion. The trigonal-bipyramidal ThF5 - anion (calculated electron detachment energy of 7.17 eV) increases at the expense of ThF3(F2) and F3- on full mercury arc irradiation. [ThF3+][F 2-] is shown by calculations to be an ionic complex with a side-bound F2- subunit. This paper reports the first evidence for novel pentacoordinated thorium species including the unique [ThF3+][F2-] ionic radical-ion pair molecule and its electron-capture product, the very stable ThF5 - anion.
- Andrews, Lester,Thanthiriwatte, K. Sahan,Wang, Xuefeng,Dixon, David A.
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p. 8228 - 8233
(2013/08/23)
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- Quantum-chemical calculations and IR spectra of the (F2)MF 2 molecules (M = B, Al, Ga, In, Tl) in solid matrices: A new class of very high electron affinity neutral molecules
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Electron-deficient group 13 metals react with F2 to give the compounds MF2 (M = B, Al, Ga, In, Tl), which combine with F 2 to form a new class of very high electron affinity neutral molecules, (F2)MF2, in solid argon and neon. These (F 2)MF2 fluorine metal difluoride molecules were identified through matrix IR spectra containing new antisymmetric and symmetric M-F stretching modes. The assignments were confirmed through close comparisons with frequency calculations using DFT methods, which were calibrated against the MF3 molecules observed in all of the spectra. Electron affinities calculated at the CCSD(T) level fall between 7.0 and 7.8 eV, which are in the range of the highest known electron affinities.
- Wang, Xuefeng,Andrews, Lester
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p. 3768 - 3771
(2011/04/26)
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- Matrix IR spectra of the products from F2, ClF, and Cl2 reactions with pulsed-laser evaporated uranium atoms
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Pulsed Nd:YAG laser ablated uranium atoms were codeposited with F2 and excess Ar onto a CsI window at 12 K. Infrared spectra revealed the presence of several uranium fluorides including the previously characterized UF4, UF5, and UF6. Lower laser energy favored new absorptions at 400, 446, 496, and 561 cm-1. These product absorptions increased stepwise during annealings which permitted diffusion and reaction of the fluorine. Similar studies with ClF produced the above absorptions plus a new band at 554 cm-1 which is tentatively assigned to ClF2-. The first bands appearing at 400 and 446 cm-1 are assigned to UF and UF2, respectively. The 496- and 561-cm-1 bands are tentatively assigned to UF3 and F3-, respectively. Finally, uranium atoms were reacted with Cl2. In addition to several absorptions due to UCl4, a new doublet at 312 and 308 cm-1 is assigned to UCl2.
- Hunt, Rodney D.,Thompson, Craig,Hassanzadeh, Parviz,Andrews, Lester
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p. 388 - 391
(2008/10/08)
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