Collisional quenching of chlorine (32P12) by H2, D2, CO, O2, N2 and CO2

Sotnichenko, S. A.; Bokun, V. Ch.; Nadkhin, A. I.

doi:10.1016/0009-2614(88)85261-8

Cited by 33 publications

(12 citation statements)

References 13 publications

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“…Hence, equilibration of the spin–orbit states occurs on a time scale that is short compared to the time scale for chemical reactions under a majority of the experimental conditions employed, and it can be safely assumed that all the data reported in this study are representative of an equilibrium mixture of Cl spin–orbit states. As a further check on the assumption of spin state equilibration, a few experiments were carried out with SF 6 , a very efficient Cl( 2 P 1/2 ) quencher 39, added to the reaction mixture. These experiments were performed as part of the study of reaction (3), where the observed reaction times were shorter than in the studies of reactions (1) and (2) and, as a result, the potential for nonequilibration of the Cl spin–orbit states was the greatest.…”

Section: Resultsmentioning

confidence: 99%

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Zhao¹,

Huskey²,

Nicovich³

et al. 2008

Int J of Chemical Kinetics

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A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of the reactions of atomic chlorine with acetone (CH 3 C(O)CH 3 ; k 1 ), 2-butanone (C 2 H 5 C(O)CH 3 ; k 2 ), and 3-pentanone (C 2 H 5 C(O)C 2 H 5 ; k 3 ) as a function of temperature (210-440 K) and pressure (30-300 Torr N 2 ). No significant pressure dependence is observed for any of the reactions studied. Arrhenius expressions (units are 10 −11 cm 3 molecule −1 s −1 ) obtained from the data are k 1 (T) = (1.53 ± 0.19) exp[(−594 ± 33)/T], k 2 (T) = (2.77 ± 0.33) exp[(+76 ± 33)/T], and k 3 (T) = (5.66 ± 0.41) exp[(+87 ± 22)/T], where uncertainties are 2σ and represent precision only. The accuracy of reported rate coefficients is estimated to be ±15% over the entire range of pressure and temperature investigated. The room temperature rate coefficients reported in this study are in good agreement with a majority of literature values. However, the activation energies reported in this study are in poor agreement with the literature values, particularly for 2-butanone and 3-pentanone. Possible explanations for discrepancies in published kinetic parameters are proposed, and the potential role of Cl + ketone reactions in atmospheric chemistry is discussed. C

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Section: Resultsmentioning

confidence: 99%

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Zhao¹,

Huskey²,

Nicovich³

et al. 2008

Int J of Chemical Kinetics

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“…28,29 The rate coefficient for deactivation of Cl( 2 P 1/2 ) by N 2 is 5.0 Â 10 À15 cm 3 molecule À1 s À1 , 30 suggesting equilibration of the spin-orbit state populations should occur rapidly on the time scale for chemical reaction under a majority of the experimental conditions employed. As a further check on the assumption of spin state equilibration, a few experiments were carried out with SF 6 , a very efficient Cl( 2 P 1/2 ) quencher, 31,32 added to the reaction mixture. As expected, this variation in experimental conditions had no effect on observed kinetics.…”

Section: Resultsmentioning

confidence: 99%

Kinetics, mechanism, and thermochemistry of the gas-phase reaction of atomic chlorine with pyridine

Zhao

Huskey

Olsen

et al. 2007

Phys. Chem. Chem. Phys.

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A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of the reaction of atomic chlorine with pyridine (C(5)H(5)N) as a function of temperature (215-435 K) and pressure (25-250 Torr) in nitrogen bath gas. At T> or = 299 K, measured rate coefficients are pressure independent and a significant H/D kinetic isotope effect is observed, suggesting that hydrogen abstraction is the dominant reaction pathway. The following Arrhenius expression adequately describes all kinetic data at 299-435 K for C(5)H(5)N: k(1a) = (2.08 +/- 0.47) x 10(-11) exp[-(1410 +/- 80)/T] cm(3) molecule(-1) s(-1) (uncertainties are 2sigma, precision only). At 216 K < or =T< or = 270 K, measured rate coefficients are pressure dependent and are much faster than computed from the above Arrhenius expression for the H-abstraction pathway, suggesting that the dominant reaction pathway at low temperature is formation of a stable adduct. Over the ranges of temperature, pressure, and pyridine concentration investigated, the adduct undergoes dissociation on the time scale of our experiments (10(-5)-10(-2) s) and establishes an equilibrium with Cl and pyridine. Equilibrium constants for adduct formation and dissociation are determined from the forward and reverse rate coefficients. Second- and third-law analyses of the equilibrium data lead to the following thermochemical parameters for the addition reaction: Delta(r)H = -47.2 +/- 2.8 kJ mol(-1), Delta(r)H = -46.7 +/- 3.2 kJ mol(-1), and Delta(r)S = -98.7 +/- 6.5 J mol(-1) K(-1). The enthalpy changes derived from our data are in good agreement with ab initio calculations reported in the literature (which suggest that the adduct structure is planar and involves formation of an N-Cl sigma-bond). In conjunction with the well-known heats of formation of atomic chlorine and pyridine, the above Delta(r)H values lead to the following heats of formation for C(5)H(5)N-Cl at 298 K and 0 K: Delta(f)H = 216.0 +/- 4.1 kJ mol(-1), Delta(f)H = 233.4 +/- 4.6 kJ mol(-1). Addition of Cl to pyridine could be an important atmospheric loss process for pyridine if the C(5)H(5)N-Cl product is chemically degraded by processes that do not regenerate pyridine with high yield.

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“…In this experiment, the collisional relaxation and the chemical reaction of Cl( 2 P 1/2 ) could be ignored. The pressures of HCl and Ar buffer gas were 20 and 160 mTorr and the time delay between the photolysis and probe laser pulses was 130 ns, and the relaxation rate of Cl( 2 P 1/2 ) by collision with HCl and Ar are 7.8 × 10 −12 and ≤1.0 × 10 −14 cm 3 molecule −1 s −1 , respectively [ Hitsuda et al , 2001; Sotnichenko et al , 1988]. Twenty‐three sets of experiments were performed for photolytic calibration method.…”

Section: Resultsmentioning

confidence: 99%

Quantum yield for N(⁴S) production in the ultraviolet photolysis of N₂O

et al. 2003

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[1] Direct detection of N( 4 S) atom formation in the 193 nm photolysis of N 2 O by a technique of vacuum ultraviolet (vuv) laser-induced fluorescence spectroscopy has been reported. Tunable vuv laser radiation around 120.071 nm that is resonant to the onephoton N(2p 2 3s 4 P 1/2 À 2p 3 4 S 3/2 ) transition has been generated by two-photon resonant four-wave sum frequency mixing in Hg vapor. The quantum yield value for N( 4 S) formation in the N 2 O photolysis at 193 nm has been determined to be 2.1 (±0.9) Â 10 À3 . The N( 4 S) detection technique, which is developed in this study, is very sensitive, and the minimum detection limit is estimated to be 2 Â 10 9 atoms cm À3. Impact of the photolytic N( 4 S) and NO(X 2 Å) production from N 2 O photolysis on stratospheric chemistry has been explored using a one-dimensional photochemical model, while the fragmentation was not considered in former model calculations. When the N( 4 S) + NO dissociation channel is considered in the photochemical model, an enhancement of the NO x production rate (up to 3%) is observed, which is followed by a decrease of the steady state O 3 concentration throughout the stratosphere.

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Collisional quenching of chlorine (32P12) by H2, D2, CO, O2, N2 and CO2

Cited by 33 publications

References 13 publications

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Kinetics, mechanism, and thermochemistry of the gas-phase reaction of atomic chlorine with pyridine

Quantum yield for N(⁴S) production in the ultraviolet photolysis of N₂O

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Collisional quenching of chlorine (32P12) by H2, D2, CO, O2, N2 and CO2

Cited by 33 publications

References 13 publications

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Temperature‐dependent kinetics study of the gas‐phase reactions of atomic chlorine with acetone, 2‐butanone, and 3‐pentanone

Kinetics, mechanism, and thermochemistry of the gas-phase reaction of atomic chlorine with pyridine

Quantum yield for N(4S) production in the ultraviolet photolysis of N2O

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Quantum yield for N(⁴S) production in the ultraviolet photolysis of N₂O