title: Properties of ThF(x) from infrared spectra in solid argon and neon with supporting electronic structure and thermochemical calculations.
abstract: Laser-ablated Th atoms react with F2 in condensing noble gases to give ThF4 as the major product. Weaker higher frequency infrared absorptions at 567.2, 564.8 (576.1, 573.8) cm(-1), 575.1 (582.7) cm(-1) and 531.0, (537.4) cm(-1) in solid argon (neon) are assigned to the ThF, ThF2 and ThF3 molecules based on annealing and photolysis behavior and agreement with CCSD(T)/aug-cc-pVTZ vibrational frequency calculations. Bands at 528.4 cm(-1) and 460 cm(-1) with higher fluorine concentrations are assigned to the penta-coordinated species (ThF3)(F2) and ThF5(-). These bands shift to 544.2 and 464 cm(-1) in solid neon. The ThF5 molecule has the (ThF3)(F2) Cs structure and is essentially the unique [ThF3(+)][F2(-)] ion pair based on charge and spin density calculations. Electron capture by (ThF3)(F2) forms the trigonal bipyramidal ThF5(-) anion in a highly exothermic process. Extensive structure and frequency calculations were also done for thorium oxyfluorides and Th2F4,6,8 dimer species. The calculations provide the ionization potentials, electron affinities, fluoride affinities, Th-F bond dissociation energies, and the energies to bind F2 and F2(-) to a cluster as well as dimerization energies.
authors.affiliation: Department of Chemistry, The University of Alabama , Tuscaloosa, Alabama 35487-0336, United States.
authors.forename: K Sahan
authors.initials: KS
authors.lastname: Thanthiriwatte
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.forename: Lester
authors.initials: L
authors.lastname: Andrews
authors.forename: David A
authors.initials: DA
authors.lastname: Dixon
authors.forename: Jens
authors.initials: J
authors.lastname: Metzger
authors.forename: Thomas
authors.initials: T
authors.lastname: Vent-Schmidt
authors.forename: Sebastian
authors.initials: S
authors.lastname: Riedel