- Temperature dependent rate constants for the reactions of gas phase lanthanides with N2O
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The reactivity of gas phase lanthanide (Ln) atoms (Ln=La-Yb with the exception of Pm) with N2O from 298 to 623 K is reported. Lanthanide atoms were produced by the photodissociation of Ln(TMHD)3 (TMHD=2,2,6,6-tetramethyl-3,5-heptanat
- Campbell, Mark L.
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- Temperature-Dependent Rate Constants for the Reactions of Gas-Phase Lanthanides with O2
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The reactivity of the gas-phase lanthanide atoms Ln (Ln = La-Yb with the exception of Pm) with O2 is reported. Lanthanide atoms were produced by the photodissociation of [Ln(TMHD)3] and detected by laser-induced fluorescence. For all the lanthanides studied with the exception of Yb, the reaction mechanism is bimolecular abstraction of an oxygen atom. The bimolecular rate constants (in molecule-1 cm3 s-1) are described in Arrhenius form by k[Ce(1G4)] = (3.0 ± 0.4) × 10-10 exp(-3.4 ± 1.3 kJ mol-1/RT); Pr(4I9/2), (3.1 ± 0.7) × 10-10 exp(-5.3 ± 1.5 kJ mol-1/RT); Nd(5I4), (3.6 ± 0.3) × 10-10 exp(-6.2 ± 0.4 kJ mol-1/RT); Sm(7F0), (2.4 ± 0.4) × 10-10 exp(-6.2 ± 1.5 kJ mol-1/RT); Eu(8S7/2), (1.7 ± 0.3) × 10-10 exp(-9.6 ± 0.7 kJ mol-1/RT); Gd(9D2), (2.7 ± 0.3) × 10-10 exp(-5.2 ± 0.8 kJ mol-1/RT); Tb(6H15/2), (3.5 ± 0.6) × 10-10 exp(-7.2 ± 0.8 kJ mol-1/RT); Dy(5I8), (2.8 ± 0.6) × 10-10 exp(-9.1 ± 0.9 kJ mol-1/RT); Ho(4I15/2), (2.4 ± 0.4) × 10-10 exp(-9.4 ± 0.8 kJ mol-1/RT); Er(3H6), (3.0 ± 0.8) × 10-10 exp(-10.6 ± 1.1 kJ mol-1/RT); Tm(2F7/2), (2.9 ± 0.2) × 10-10 exp(-11.1 ± 0.4 kJ mol-1/RT), where the uncertainties represent ±2σ. The reaction barriers are found to correlate to the energy required to promote an electron out of the 6s subshell. The reaction of Yb(1S0) with O2 reacts through a termolecular mechanism. The limiting low-pressure third-order rate constants are described in Arrhenius form by k0[Yb(1S0)] = (2.0 ± 1.3) × 10-28 exp(-9.5 ± 2.8 kJ mol-1/RT) molecule-2 cm6 s-1.
- Campbell, Mark L.
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p. 7274 - 7279
(2007/10/03)
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