Electronic relaxation processes in acetone and 1,1,1-trifluoroacetone vapor and the gas phase recombination of the acetyl radical at 22.degree.C

Gandini, A.; Hackett, P. A.

doi:10.1021/ja00461a005

Cited by 55 publications

(72 citation statements)

References 7 publications

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“…and that the reactivity of these radicals was consistent with the attainment of thermal equilibrium at room temperature [3]. Consequently each radical species has the same limiting concentration Cmax, which is defined as the concentration which either species would have attained if all the radicals generated by the flash had been present simultaneously in the reaction cell.…”

Section: Methodsmentioning

confidence: 94%

“…The corresponding rate equations were integrated by a fourthorder Runge-Kutta procedure analogous to the one that we used for the interaction of the ethyl radical and the oxygen molecule [4]. The values of k z , k3, k q , and k6 are given elsewhere in this paper; we chose k 5 = 1 s-l as representative of the values reviewed by Gandini and Hackett [3], but the computation is insensitive to the value of this rate constant.…”

Section: Absorption Spectramentioning

confidence: 99%

“…The reported absorption spectrum resembles in outline that shown in Figure 2, although the value given for the extinction coefficient is twice our own value. The reported values of k. 3 and k4 are each one half of our own. In these comparisons agreement within a factor of 2 should be regarded as good agreement, because the values of the extinction coefficient and the rate constants given in this letter have been found by an indirect method involving both a major correction in the evaluation of k 6 / k 2 and the assumption that k 3 = 2(k2k4)lI2 for the cross combination of acetyl and methyl radicals.…”

Section: Fast Reactions Of the Acetyl Radicalmentioning

confidence: 99%

“…Kinetic spectroscopy was used to measure the rate constants of the interactions of these radicals: 2 CH; + CH3CH3 (3) CHzCO. + CH; -inactive products (4) 2 CHsCO.…”

Section: Introductionmentioning

confidence: 99%

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The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

Adachi¹,

Basco²,

James³

1981

Int J of Chemical Kinetics

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Ultraviolet absorption spectra have been characterized for the acetyLh3 and acetyl-d.? radicals, which were generated by the flash photolysis of the corresponding acetones. The spectra are broad and intense, with values of the extinction coefficient at the respective maxima estimated as: tcH3co (215) were estimated as: k y = 8.6 X 1O1O L/mol-s and k: = 5.2 X 1O1O L/mol-s. The related values of the cross interaction ratios k y / ( k y k y ) 1 / 2 = 2.6 and k y / ( k ? k f ) l / z = 1.6 do not differ significantly from the statistical value of 2. The participation of the radical displacement reactions 2 CH3CO' -all products 2 CD3CO -all products CH; + CH&O -all products CD; + CD&O -all products CH; + CH3CO -CH3CHs + CO CD; + CDzCO' -CD3CDs + CO was estimated in terms of the fractions kyb/ky = 0.38 and kFb/kF = 0.47.Corroborative spectra were obtained from the flash photolysis of methyl ethyl ketone and biacetyl, and the relative rates of the competing primary processes were estimated from the relative peak heights of the acetyl and methyl radicals in each system.

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Section: Methodsmentioning

confidence: 94%

Section: Absorption Spectramentioning

confidence: 99%

Section: Fast Reactions Of the Acetyl Radicalmentioning

confidence: 99%

“…Kinetic spectroscopy was used to measure the rate constants of the interactions of these radicals: 2 CH; + CH3CH3 (3) CHzCO. + CH; -inactive products (4) 2 CHsCO.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

Adachi¹,

Basco²,

James³

1981

Int J of Chemical Kinetics

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“…By photo-irradiation to the complex, the electronic state is vertically changed to the first and second excited states (S 1 and S 2 ). In case of acetone, intersystem crossing (ISC) from singlet to triplet states occurs efficiently (quantum yield of ISC is 0.53±0.04) [23][24][25] and the surface is changed to the T 1 state. Therefore, the hydrogen abstraction reaction is exothermic in the energetics.…”

Section: Methods Of Calculationmentioning

confidence: 99%

Direct ab initio MD study on the hydrogen abstraction reaction of triplet state acetone from methanol molecule

Tachikawa

Kawabata

2010

Theor Chem Acc

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Solvent re-orientation process of triplet acetone-methanol complex and intermolecular hydrogen atom abstraction reaction on the triplet state energy surface, (CH 3 ) 2 C=O (T 1 ) + CH 3 OH → (CH 3 ) 2 C-OH + CH 2 OH in gas phase, have been investigated by means of density functional theory (DFT) and direct ab-initio molecular dynamics (MD) methods. The static DFT calculation of hydrogen abstraction reaction at the T 1 state showed that the transition state is 16.4 and 30.9 kcal/mol lower than the energy levels of S 1 and S 2 states, respectively, and 9.2 kcal/mol higher than the bottom of T 1 state. The product state, (CH 3 ) 2 C-OH--CH 2 OH, is 8.4 kcal/mol lower in energy than the level of T 1 state. The direct ab-initio MD calculation showed that the product is rapidly formed within 150 fs and the separated products (CH 3 ) 2 C-OH + CH 2 OH were formed. The mechanism of reaction dynamics of the triplet acetone-methanol complex was discussed on the basis of theoretical results.

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Photodissociation of acetone revisited: Femtosecond transient absorption of S₁ state and highly excited Rydberg state in the gas phase

Jin

Yang

Kim

2022

Bulletin Korean Chem Soc

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Photodissociation dynamics of acetone in gas phase were, for the first time, investigated using the pump‐probe technique of femtosecond transient absorption. To obtain a genuine time profile of nR state, we employed 200‐nm and 400‐nm pulses for two‐photon excitation and three‐photon excitation, respectively. In gas phase of acetone, the extraordinarily stable nR state originated from nR states in the Franck–Condon region, whose decay time constant was 350 ± 10 fs, was observed after excitation by three‐photon absorption of 400‐nm pulses. In the low‐power case of 267 nm, the photodissociation dynamics in the S1 state by one‐photon absorption showed that acetone was completely dissociated into two methyl radicals and C=O via an acetyl radical intermediate with a lifetime of 200 ± 10 fs. In the high‐power case of 267‐nm light, we interpreted the transient, although this is a subject of ongoing debate, as caused by both the photodissociation dynamics of the S1 state for a fast component and the dynamics of nR states for long‐lived species.

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Electronic relaxation processes in acetone and 1,1,1-trifluoroacetone vapor and the gas phase recombination of the acetyl radical at 22.degree.C

Cited by 55 publications

References 7 publications

The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

Direct ab initio MD study on the hydrogen abstraction reaction of triplet state acetone from methanol molecule

Photodissociation of acetone revisited: Femtosecond transient absorption of S₁ state and highly excited Rydberg state in the gas phase

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Electronic relaxation processes in acetone and 1,1,1-trifluoroacetone vapor and the gas phase recombination of the acetyl radical at 22.degree.C

Cited by 55 publications

References 7 publications

The acetyl radicals CH3CO· and CD3CO· studied by flash photolysis and kinetic spectroscopy

The acetyl radicals CH3CO· and CD3CO· studied by flash photolysis and kinetic spectroscopy

Direct ab initio MD study on the hydrogen abstraction reaction of triplet state acetone from methanol molecule

Photodissociation of acetone revisited: Femtosecond transient absorption of S1 state and highly excited Rydberg state in the gas phase

Contact Info

Product

Resources

About

The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

The acetyl radicals CH₃CO· and CD₃CO· studied by flash photolysis and kinetic spectroscopy

Photodissociation of acetone revisited: Femtosecond transient absorption of S₁ state and highly excited Rydberg state in the gas phase