Reactive Chlorine Compounds in the Atmosphere

Khalil, M. A. K.

doi:10.1007/10628761_2

Cited by 23 publications

(17 citation statements)

References 81 publications

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“…Winds disperse the gas and, even downwind from the cone summit, Cl 2 concentrations rapidly decrease. Cl 2 has a tropospheric lifetime of several hours (Khalil, 1999;Winterton, 2000) and during this time, much of the Cl 2 reacts with H 2 or VOC to form HCl or chlorinated organics. Within the chlorine -containing plume, tropospheric ozone loss can also occur (Platt and Hö nninger, 2003).…”

Section: Volcanic Emissions Of CLmentioning

confidence: 99%

Volcanic emissions of molecular chlorine

Zelenski

Taran

2012

Geochimica et Cosmochimica Acta

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Section: Volcanic Emissions Of CLmentioning

confidence: 99%

Volcanic emissions of molecular chlorine

Zelenski

Taran

2012

Geochimica et Cosmochimica Acta

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“…Of these three variables, the atmospheric concentration is often the best known, as is the case for the gases included here. We will discuss these components for each of the chlorine-containing gases of interest [see also Keene et al, 1990; Graedel and Keene, 1995; Khalil, 1998]. …”

Section: Concentration Distribution Of Reactive Chlorine Gasesmentioning

confidence: 99%

Natural emissions of chlorine‐containing gases: Reactive Chlorine Emissions Inventory

Khalil¹,

Moore²,

Harper³

et al. 1999

J. Geophys. Res.

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178

163

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Abstract. Although there are many chlorine-containing trace gases in the atmosphere, only those with atmospheric lifetimes of 2 years or fewer appear to have significant natural sources. The most abundant of these gases are methyl chloride, chloroform, dichloromethane, perchloroethylene, and trichloroethylene. Methyl chloride represents about 540 parts per trillion by volume (pptv) C1, while the others together amount to about 120 pptv C1. For methyl chloride and chloroform, both oceanic and land-based natural emissions have been identified. For the other gases, there is evidence of oceanic emissions, but the roles of the soils and land are not known and have not been studied. The global annual emission rates from the oceans are estimated to be 460 Gg C1/yr for CH3C1, 320 Gg C1/yr for CHC13, 160 Gg C1/yr for CH2C12, and about 20 Gg C1/yr for each of C2HC13, and C2C14. Land-based emissions are estimated to be 100 Gg C1/yr for CH3C1 and 200 Gg C1/yr for CHC13. These results suggest that the oceans account for about 12% of the global annual emissions of methyl chloride, although until now oceans were thought to be the major source. For chloroform, natural emissions from the oceans and lands appear to be the major sources. For further research, the complete database compiled for this work is available from the archive, which includes a monthly emissions inventory on a 1øxl ø latitude-longitude grid for oceanic emissions of methyl chloride.

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“…1 It is well known that Cl atoms catalyse O 3 decomposition. 2 A very signicant percentage of CH 3 Cl comes from natural sources, 3 making it a particularly important compound.…”

Section: Introductionmentioning

confidence: 99%

Valence and Rydberg states of CH₃Cl: a MR-CISD study

2014

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In this work ten singlet and nine triplet states are studied through multi-reference configuration interactions with singles and doubles (MR-CISD), including Davidson extensivity correction (MR-CISD+Q). For the first time the excited states whose energies are larger than $9.5 eV have been calculated using highly correlated methods. The energies, spatial extent (hr 2 i), configurations weights and oscillator strengths (f) have been computed. At the MR-CISD+Q level the excited states energies vary from $7.51 to 11.98 eV. The lowest (ns*) excited singlet state is significantly mixed with the n3p a1 and n3s Rydberg states, while the next (n3s) has a non-negligible mixture with the ns* state. The next three singlet states obtained result from the (n Cl ) 3 (3p e ) 1 configuration and are almost degenerate. The next (n3p a1 ) singlet state is significantly mixed with the ns* state, while the last three have s C-Cl / Rydberg (3s or 3p) as the main configurations. According to the f values the most intense transition is to the 4 1 A 1 state, a s3p a1 Rydberg state mixed with the ss* and s3s configurations. Our results indicate that the ss* configuration is responsible for the high f value of the gs / 4 1 A 1 transition. The Rydberg-valence mixing is greatly reduced in the triplet states whose singlet counterparts have significant multiconfigurational character.The 2 3 A 1 state (ss*) does not have its singlet counterpart, while the 4 1 A 1 state (s3p a1 + ss* + s3s) does not have its triplet counterpart. The obtained results are in good agreement with experimental results and with previous CASPT2 results.

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Reactive Chlorine Compounds in the Atmosphere

Cited by 23 publications

References 81 publications

Volcanic emissions of molecular chlorine

Volcanic emissions of molecular chlorine

Natural emissions of chlorine‐containing gases: Reactive Chlorine Emissions Inventory

Valence and Rydberg states of CH₃Cl: a MR-CISD study

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Reactive Chlorine Compounds in the Atmosphere

Cited by 23 publications

References 81 publications

Volcanic emissions of molecular chlorine

Volcanic emissions of molecular chlorine

Natural emissions of chlorine‐containing gases: Reactive Chlorine Emissions Inventory

Valence and Rydberg states of CH3Cl: a MR-CISD study

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Valence and Rydberg states of CH₃Cl: a MR-CISD study