Quantum yield for NO3 production from photolysis of ClONO2

Marinelli, William J.; Johnston, Herrick L.

doi:10.1016/0009-2614(82)83678-6

Cited by 16 publications

(15 citation statements)

References 9 publications

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“…These results are in excellent agreement with two other studies of the chlorine nitrate branching ratios. 5,8 For photolysis in the unfiltered quartz cell (λ > 200 nm), the relative branching ratios are 0.61 ( 0.20 for the ClO + NO 2 channel and 0.31 ( 0.20 for the Cl + NO 3 channel.…”

Section: Discussionmentioning

confidence: 99%

“…A number of previous studies have examined the branching ratios among the various dissociation pathways. [1][2][3][4][5][6][7][8][9] In 1983, Margitan reported that branching among the possible product channels was dominated by reaction 1b, with 90% of dissociation occurring via this process and the remaining 10% proceeding via reaction 1c at 266 and 355 nm. 6 He saw no evidence of the ClO product from reaction 1a even though dissociation via this channel cleaves the weakest bond in the molecule.…”

Section: Introductionmentioning

confidence: 99%

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Pressure-Dependent Yields and Product Branching Ratios in the Broadband Photolysis of Chlorine Nitrate

1996

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The photolysis of chlorine nitrate was studied using broadband flash photolysis coupled with long-path ultraviolet-visible absorption spectroscopy. Branching ratios for the Cl + NO 3 and ClO + NO 2 product channels were determined from time-dependent measurements of ClO and NO 3 concentrations. Yields of the ClO and NO 3 products displayed a dependence on the bath gas density and the spectral distribution of the photolysis pulse. Product yields decreased with increasing bath gas density regardless of the spectral distribution of the photolysis pulse; however, the decrease in product yield was much more pronounced when photolysis was limited to longer wavelengths. For photolysis in a quartz cell (λ > 200 nm) the yield decreased by a factor of 2 over the pressure 10-100 Torr. In a Pyrex cell (λ > 300 nm), the yield decreased by a factor of 50 over the same pressure range. When photolysis was limited to λ > 350 nm, the yield decreased by a factor of 250. Branching ratios for the photolysis channels [ClONO 2 + hν f ClO + NO 2 (1a) and ClONO 2 + hν f Cl + NO 3 (1b)] were determined from the relative ClO and NO 3 product yields at various pressures. Although the absolute product yield displayed a pressure dependence, the branching between the two channels was independent of pressure. The relative branching ratios (assuming negligible contributions from other channels) are 0.61 ( 0.20 for channel 1a and 0.39 ( 0.20 for channel 1b for photolysis with λ > 200 nm and 0.44 ( 0.08 for channel 1a and 0.56 ( 0.08 for channel 1b for photolysis with λ > 300 nm. The implications of these results for the chemistry of the lower stratosphere are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pressure-Dependent Yields and Product Branching Ratios in the Broadband Photolysis of Chlorine Nitrate

1996

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“…CIONO2 was prepared by reacting N2Os with C12 O, according to the method of Schmeisser (1967), followed by purification as described by Marinelli and Johnston (1982). The purity of the C1ONO2 was checked by FT-IR measurements.…”

Section: Methodsmentioning

confidence: 99%

The gas-phase reaction of ClONO2 with hydrogen chloride

et al. 1987

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The gas-phase reaction ofC1ONO 2 with HC1 was investigated using two large-volume environmental chambers with analysis by in situ long pathlength Fourier transform infrared absorption spectroscopy. In these chambers the reaction was observed to proceed, at least in part, by heterogeneous routes, and an upper limit to the rate constant for the homogeneous gas-phase reaction of k(C1ONO 2 + HC1) < 1.5 x 10 -t9 cm 3 molecule -~ s -1 was derived at 298-+ 2K. Assuming that this room-temperature upper limit to the rate constant is applicable to stratospheric temperatures, this homogeneous gas-phase reaction can be estimated to be of negligible importance as a C1ONO 2 loss process in the stratosphere.

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“…Polyphyletic (A and B) and mphyletic (C and D) hypotheses of arthropod relationships. Polyphyletic hypotheses propose either that (A) onychophorans are more closely related to certain annelids than to arthropods (2) or (8) arthropodization has occurred independently at least three times (3). Hypotheses of arthropod monophyfy Propose onychophorans are either (C) primitive (4) or (D) closely allied to myriapods and hexapods (5).…”

Section: Chophorans Maximum Parsimony Analyses and Monophyly Testingmentioning

confidence: 99%

Direct Observation of ClO from Chlorine Nitrate Photolysis

Minton

Nelson

Moore

et al. 1992

Science

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Chlorine nitrate photolysis has been investigated with the use of a molecular beam technique. Excitation at both 248 and 193 nanometers led to photodissociation by two pathways, CIONO(2) --> CIO + NO()2 and CIONO(2) --> Cl + NO3, with comparable yields. This experiment provides a direct measurement of the CIO product channel and consequently raises the possibility of an analogous channel in CIO dimer photolysis. Photodissociation of the CIO dimer is a critical step in the catalytic cycle that is presumed to dominate polar stratospheric ozone destruction. A substantial yield of CIO would reduce the efficiency of this cycle.

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Quantum yield for NO3 production from photolysis of ClONO2

Cited by 16 publications

References 9 publications

Pressure-Dependent Yields and Product Branching Ratios in the Broadband Photolysis of Chlorine Nitrate

Pressure-Dependent Yields and Product Branching Ratios in the Broadband Photolysis of Chlorine Nitrate

The gas-phase reaction of ClONO2 with hydrogen chloride

Direct Observation of ClO from Chlorine Nitrate Photolysis

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