Mark L. Campbell

Kinetic study of the reaction of Fe(a5DJ) with N2O from 398 to 720 K

Abstract The gas phase reactivity of Fe(a 5DJ) with N2O in the temperature range 398–620 K is reported. Iron atoms were produced by the photodissociation of ferrocene and detected by laser-induced fluorescence. The reaction rates of the a 5DJ states are very slow and temperature dependent. The bimolecular rate constant is described in Arrhenius form by (1.41 ± 0.29) × 10−10 exp(−44.4 ± 1.0 kJ/mol/RT) cm3 s−1 where the uncertainties are ±2σ. The disappearance rates in the presence of N2O are independent of buffer gas identity (Ar or N2) and total pressure. The removal rate constants for the a 5DJ states are independent of J.

Reaction kinetics of Mo(a7S3, a5S2, a5DJ, a5GJ) with O2

Abstract The gas phase reactivities of Mo ( a 7 S 3 , a 5 S 2 , a 5 D J , a 5 G J ) with O2 with O2 in the temperature range 297–620 K are reported. Mo atoms were produced by the photodissociation of Mo(CO)6 and MoCl4 and detected by laser-induced fluorescence. The disappearance rates of all states are found to be pressure independent with argon buffer gas. The disappearance rate constants of the s 1 d 5 a 7 S 3 , a 5 S 2 and a 5 G J states are on the order of the gas kinetic rate constant. The s2d4a5DJ states are not as reactive and are found to be temperature dependent. Results are discussed in terms of the different electron configurations of the states.

Kinetic study of the reaction of Mn(a6S5/2) with N2O from 448 to 620 K

The gas phase reactivity of Mn(a6S5/2) with N2O in the temperature range 448–620 K is reported. Manganese atoms were produced by the photodissociation of 2‐methylcyclopentadienyl manganese tricarbonyl and detected by laser‐induced fluorescence. The reaction rate of the a6S5/2 state is very slow and temperature dependent. The rate constants are independent of total pressure indicating a bimolecular reaction. The rate constants are described in Arrhenius form by (2.05±0.45)×10−10 exp(−44.7±1.0 kJ/mol/RT) cm3 s−1.

Temperature dependent study of the kinetics of Sc(a2D32) with O2, N2O, CO2, NO and SO2

Abstract The gas phase reactivity of Sc ( a 2 D 3 2 ) with O 2 , N 2 O, CO 2 , NO and SO 2 in the temperature range 298–523 K is reported. The bimolecular rate constants are described in Arrhenius form by k (O) 2 ) = (1.7 ± 0.4) × 10 −10 exp(−7.9 ± 0.7 kJ/mol/ RT ) cm 3 s −1 , k (N 2 O) = (1.7 ± 0.3) × 10 −10 exp)−12.0 ± 0.6 kJ/mol/ RT ) cm 3 s −1 , k (CO 2 ) = (7.3 ± 1.3) × 10 −11 exp(−12.3 ± 0.6 kJ/mol/ RT ) cm 3 s −1 where the uncertainties are ±2 σ . The rate constants with NO and SO 2 were temperature insensitive with room temperature rate constants of 1.5 × 10 −11 and 2.0 × 10 −10 cm 3 s −1 , respectively. The disappearance rates for all the reactants are independent of total pressure indicating a bimolecular abstraction mechanism.

Temperature-dependent studies of the reaction of W(a 5DJ, a 7S3) with O2

The gas-phase reactivities of W(a 5DJ, a 7S3) with O2 in the temperature range 298–573 K are reported. Tungsten atoms were produced by the photodissociation of W(CO)6 and detected by laser-induced fluorescence. The disappearance rate constant of the s1d5 a 7S3 state is of the order of the gas kinetic rate constant. The removal rate constants for the s2d4 a 5DJ states are J dependent. The a 5DJ states are not as reactive as the s1d5 a 7S3 state and are found to be temperature dependent. The disappearance rates of all states in the presence of O2 are found to be pressure independent with buffer gas. Physical quenching rate constants for the excited states in the presence of Ar, He, N2 and SF6 are also reported. Results are discussed in terms of the different electron configurations of the states.

Temperature dependent rate constants for the reactions of gas phase lanthanides with N2O

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-heptanato ion) and detected by laser-induced fluorescence. Large variations in the reaction rate constants are observed. The bimolecular rate constants are described in Arrhenius form by k[Ce(1G4)]=(1.9±0.5)×10−10 exp(−0.8±0.8 kJ mol−1/RT); Pr(4I9/2), (3.6±1.2)×10−10 exp(−8.0±1.2 kJ mol−1/RT); Nd(5I4), (3.4±0.4)×10−10 exp(−8.8±0.5 kJ mol−1/RT); Sm(7F0), (3.2±1.1)×10−10 exp(−11.2±1.2 kJ mol−1/RT); Eu(8S7/2), (2.7±0.4)±10−10 exp(−12.7±0.5 kJ mol−1/RT); Gd(9D2), (2.0±0.3)×10−10 exp(−6.4±0.5 kJ mol−1/RT); Tb(6H15/2), (2.9±0.5)×10−10 exp(−10.9±0.6 kJ mol−1/RT); Dy(5I8), (3.4±0.8)×10−10 exp(−16.2±0.8 kJ mol−1/RT); Ho(4I15/2), (2.9±0.5)×10−10 exp(−17.1±0.6 kJ mol−1/RT); Er(3H6), (3.3±1.2)×10−10 exp(−18.4±1.2 kJ mol−1/RT); Tm(2F7/2), (3.5±0.6)×10−10 exp(−19.5±0.6 kJ mol−1/RT); Yb(1S0), (2.5±0...

Kinetic study of gas-phase Lu(2D3/2) with O2, N2O and CO2

Abstract The second-order rate constants of gas-phase Lu ( 2 D 3/2 ) with O 2 , N 2 O and CO2 from 348 to 573 K are reported. In all cases, the reactions are relatively fast with small barriers. The disappearance rates are independent of total pressure indicating bimolecular abstraction processes. The bimolecular rate constants (in molecule −1 cm 3 s −1 ) are described in Arrhenius form by k( O 2 )=(2.3±0.4)×10 −10 exp (−3.1±0.7 kJ mol −1 /RT), k( N 2 O )=(2.2±0.4)×10 −10 exp (−7.1±0.8 kJ mol −1 /RT), k( CO 2 )=(2.0±0.6)×10 −10 exp (−7.6±1.3 kJ mol −1 /RT) , where the uncertainties are ±2σ.

Depletion kinetics of low‐lying states of tungsten in the presence of NO, N2O, and SO2

The gas-phase reactivities of W(a5DJ, a7S3) with N2O, SO2, and NO in the temperature range of 295–573 K are reported. Tungsten atoms produced by the photodissociation of W(CO)6. The tungsten atoms were detected by a laser-induced fluorescence technique. The removal rate constants for the 6s25d4 a5Dl states were found to be pressure dependent for all of the reactants. Removal rate constants for the 6s15d5 a7S3 state were found to be fast compared to the a5DJ states and often approached the gas kinetic rate constant. The reaction rates for all the states were found to be pressure independent with respect to the total pressure. Results are discussed in terms of the different electronic configurations of the states of tungsten

Kinetics of the termolecular reaction of gas phase Pd(a1S0) atoms with methane

Abstract The gas-phase removal rate constants for the reaction of ground state palladium (a1S0) with methane in argon buffer are reported as a function of total pressure and temperature. The pressure dependence indicates a termolecular mechanism. The limiting low-pressure third-order rate constant, k0, in argon buffer at room temperature is (2.0±0.7)×10 −30 molecule −2 cm 6 s −1 . Second-order rate constants were measured at 20.0 Torr from 348 to 523 K. Derived third-order rate constants can be expressed as logk0(T)=−201.5+141(logT)−29(logT)2 over the temperature range 294–523 K.

Gas-phase kinetics of ground-state platinum with O2,NO, N2Oand CH4

The gas-phase reactivity of ground-state platinum with O2, NO, N2O and CH4 is reported. Platinum atoms were produced by the photodissociation of [Pt(CH3)3(C5H4CH3)] and detected by laser-induced fluorescence. The reaction rates of platinum with all the reactants are pressure dependent indicating adduct formation; however, the reaction with N2O has a bimolecular component. The room-temperature limiting low-pressure third-order rate constants in argon buffer are (2.3±0.2)×10-31 molecule-2 cm6 s-1, (4.3±0.4)×10-31 molecule-2 cm6 s-1, (3.7±0.5)×10-31 molecule-2 cm6 s-1 and (2.1±0.9)×10-28 molecule-2 cm6 s-1 for O2, NO, N2O and CH4, respectively, where the uncertainties are ±2σ. The limiting high-pressure second-order rate constants are (2.5±0.5)×10-12 molecule-1 cm3 s-1, (2.3±0.8)×10-11 molecule-1 cm3 s-1, (2.3±0.3)×10-12 molecule-1 cm3 s-1 and (6.3±0.3)×10-12 molecule-1 cm3 s-1 for O2, NO, N2O and CH4, respectively. The second-order rate constant for the abstraction channel for the reaction with N2O at 296 K is approximately 1×10-13 molecule-1 cm3 s-1.