Kinetics of C2O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm

Becker, K. H.; König, Roland; Meuser, R.; Wiesen, Peter; Bayes, Kyle D.

doi:10.1016/1010-6030(92)85089-d

Cited by 19 publications

(5 citation statements)

References 22 publications

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“…There are limited reports on the rate constants of compounds , , and . It can be seen that the studies of Husain, Beckler, and Stedman have overestimated the rate constants for reactions 4, 5, and 7, respectively, − and in our present calculation, the rate constant for at a temperature of 298 K and a pressure of 0.1 atm is 3.9 × 10 –29 cm –3 molecule –1 s –1 , which is significantly lower than the upper limit estimate of Stedman et al and is 4 orders of magnitude different from the initial report of Pressman et al This error is within the allowable range, despite the gap. The large errors between the calculated and experimental values for reactions and may be due to the fact that we overestimated the height of the potential barrier.…”

Section: Resultscontrasting

confidence: 77%

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide

Tang,

Yang,

Cao

et al. 2024

J. Phys. Chem. A

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We investigate the reaction pathways of nine important CO 2 -related reactions using the revDSD-PBEP86-D3(BJ)/jun-cc-pV(T+d)Z level and simultaneously employ an accurate composite method (jun-Cheap) based on coupled-cluster (CC) theory. Subsequently, the Rice− Ramsperger−Kassel−Marcus/master equation (RRKM/ME) is solved to calculate the temperatureand pressure-dependent rate constants. This work investigates reactions involving transition states that have been overlooked in previous literature, including the dissociation of singlet-state C 3 O 2 , the triple channel formation of C 2 O + CO to form C 3 O 2 , and the formation of O 3 + CO. The results show that CO 3 is highly prone to dissociation at high temperatures. Finally, the kinetic data show that over a wide temperature range, our calculations are consistent with previous experimental measurements. The majority of the reaction rate constants studied exhibit significant pressure dependence, while the O 3 + CO reaction is pressure-independent at low temperatures. These results are instrumental in the development of detailed kinetic models for the CO 2 radiolysis reaction network.

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Section: Resultscontrasting

confidence: 77%

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide

Tang,

Yang,

Cao

et al. 2024

J. Phys. Chem. A

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“…The photolysis of C 3 O 2 at 248 nm has been investigated by Becker et al They concluded that one of the singlet states of C 2 O, probably C 2 O(a 1 Δ), is formed as an initial photolysis product. This species remained in their system for more than 200 μs, was not noticeably quenched by Ar, but reacted rapidly with C 3 O 2 .…”

Section: Discussionmentioning

confidence: 99%

Photolysis of Ketene at 193 nm and the Rate Constant for H + HCCO at 297 K

2000

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The 193 nm photolysis of ketene was studied by measuring the amount of atomic hydrogen produced when very dilute ketene/Ar and ketene/H 2 mixtures were irradiated by a single pulse from an ArF excimer laser. Absolute concentrations of atomic hydrogen were monitored over a time interval of 0-2.5 ms by using Lyman-R atomic resonance absorption spectroscopy (ARAS). Four different photodissociation channels of ketene were identified: H 2 CCO + hν gives (a) CH 2 ( 3 B 1 ) + CO; (b) CH 2 ( 1 A 1 ) + CO; (c) HCCO + H; and (d) C 2 O(b 1 Σ + ) + H 2 . The quantum yields for each channel were measured as φ a ) 0.628, φ b ) 0.193, φ c ) 0.107, and φ d ) 0.072, respectively. To explore the secondary chemistry that occurred when using higher pressure H 2 CCO/Ar mixtures, a mechanism was constructed that used well-documented reactions and, for most processes, rate constants that had already been accurately determined. Modeling studies using this mechanism showed the [H] profile to be determined largely by the rate of the reaction H + HCCO f CH 2 + CO. An excellent fit to all of the experimental data was obtained when k 2 ) (1.7 ( 0.3) × 10 -10 cm 3 molecule -1 s -1 .

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“…Triplet CCO radicals are not observed under collisionless photolysis conditions, but are seen in the presence of collisions, presumably due to collisional quenching of singlet CCO. 10,27,29 In this paper, we investigate the photodissociation spectroscopy and dynamics of triplet and singlet CCO using our fast radical beam photofragment translational spectrometer. In this experiment, CCO is generated by photodetachment of CCO Ϫ and subsequently photodissociated.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation of triplet and singlet states of the CCO radical

Choi

Mordaunt

Bise

et al. 1998

The Journal of Chemical Physics

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The triplet and singlet states of the ketenylidene ͑CCO͒ radical are investigated using fast radical beam photofragment translational spectroscopy, in which CCO is generated by laser photodetachment of CCO Ϫ and subsequently photodissociated, and anion photoelectron spectroscopy. In the photodissociation experiment, two bands in which the upper state of CCO predissociates are studied. Photodissociation from excitation of the Ã 3 ⌸-X 3 ⌺ Ϫ band in CCO is observed from 16 666-23 529 cm Ϫ1 ; resonances are observed and assigned to excited vibrational levels involving all three vibrational modes. We also report the first observation of the c 1 ⌸-ã 1 ⌬ band in CCO. Here, the ã 1 ⌬ state of CCO is generated by laser photodetachment at higher photon energy than was used to generate the X 3 ⌺ state. The c 1 ⌸ state is approximately located by photoelectron spectroscopy of CCO Ϫ , and the photodissociation experiment shows that the origin of the c 1 ⌸-ã 1 ⌬ band occurs around 17 170 cm Ϫ1. Kinetic-energy release spectra from both bands yield accurate values for the C-CO bond dissociation energy and heat of formation of CCO: D 0 ͑C-CO͒ϭ2.24Ϯ0.02 eV (51.7Ϯ0.5 kcal/mol) and ⌬H f ,298 0 ͑CCO͒ϭ4.04Ϯ0.02 eV (91.1 Ϯ0.5 kcal/mol). Although the translational-energy distributions resulting from excitation to the Ã 3 ⌸ and c 1 ⌸ states are clearly nonstatistical, consideration of the potential-energy surfaces indicates that dissociation from both states occurs via radiationless transitions to the X 3 ⌺ Ϫ state.

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Kinetics of C2O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm

Cited by 19 publications

References 22 publications

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide

Photolysis of Ketene at 193 nm and the Rate Constant for H + HCCO at 297 K

Photodissociation of triplet and singlet states of the CCO radical

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Kinetics of C2O radicals formed in the photolysis of carbon suboxide at 308 and 248 nm

Cited by 19 publications

References 22 publications

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between COn (n = 0–4), Om (m = 1–3), C2O, and C3O2 during the Radiolysis of Carbon Dioxide

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between COn (n = 0–4), Om (m = 1–3), C2O, and C3O2 during the Radiolysis of Carbon Dioxide

Photolysis of Ketene at 193 nm and the Rate Constant for H + HCCO at 297 K

Photodissociation of triplet and singlet states of the CCO radical

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Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide

Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between CO_n (n = 0–4), O_m (m = 1–3), C₂O, and C₃O₂ during the Radiolysis of Carbon Dioxide