Chemiionization in alkali-halogen reactions: Evidence for ion formation by alkali dimers

Dispert, H.; Lacmann, K.

doi:10.1016/0009-2614(77)85034-3

Cited by 30 publications

(13 citation statements)

References 10 publications

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“…However, the value is precise enough to distinguish between previously published electron affinity (EA) values for FCl. − We calculate EA 0 (FCl) ≥ 249 ± 40 kJ/mol (2.6 ± 0.4 eV), shown in Table , using EA 0 (FCl) ≥ −Δ f H 0 (F - ) − Δ f H 0 (CH 3 Cl) + Δ f H 0 (CH 3 ) + Δ f H 0 (FCl) − E 0 (4) with Δ f H 0 values from Gurvich et al and our experimentally measured threshold value. Even as a lower limit, our EA measurement excludes the literature values EA(FCl) = 1.5 ± 0.3 eV from Dispert and Lacmann and Harland and Thynne . However, the EA 0 (FCl) = 2.37 ± 0.21 eV determined by Dudin et al agrees within the error bars of our measured EA 0 (FCl) ≥ 2.6 ± 0.4 eV.…”

Section: Discussionsupporting

confidence: 81%

“…d Calculated using ∆fH0(CH3F) ) -225 ( 8 kJ/ mol estimated by Kolesov,61 which agrees with theoretical calculations by Berry et al62 e Calculated using EA(CH2Cl) ) 0.80 ( 0.16 eV determined by Bartmess 40 from work by Ingemann and Nibbering 41. f Calculated using EA(FCl) ) 2.37 ( 0.21 eV from Dudin et al54 g Calculated using EA(FCl) ) 1.5 ( 0.3 eV from Dispert and Lacmann55 or Harland and Thynne. 53 h Calculated using ∆fH0(CH2F -) ) -53 ( 19 kJ/mol determined by Bartmess 40 from work by Graul et al63 i Calculated using EA(CHCl) ) 1.210 ( 0.005 eV from Gilles et al64…”

supporting

confidence: 75%

“…[51][52][53][54] We calculate EA 0 (FCl) g 249 ( 40 kJ/mol (2.6 ( 0.4 eV), shown in Table 2, using EA 0 (FCl) 47 and our experimentally measured threshold value. Even as a lower limit, our EA measurement excludes the literature values EA(FCl) ) 1.5 ( 0.3 eV from Dispert and Lacmann 55 and Harland and Thynne. 53 However, the EA 0 (FCl) ) 2.37 ( 0.21 eV determined by Dudin et al 54 agrees within the error bars of our measured EA 0 (FCl) g 2.6 ( 0.4 eV.…”

Section: Discussionmentioning

confidence: 62%

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Dynamics of the Gas-Phase Reactions of Fluoride Ions with Chloromethane

and

Ervin

2001

J. Phys. Chem. A

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Guided ion beam tandem mass spectrometry techniques are used to examine the competing chemical dynamics of reactions of fluoride ions with chloromethane in the center-of-mass collision energy range 0.05−30 eV. The exothermic bimolecular nucleophilic substitution (SN2) reaction F- + CH3Cl → CH3F + Cl- predominates at the lowest collision energies (0.05−0.1 eV) but decreases by a factor of ∼100 over the range 0.1−2 eV. Two endothermic product channels are detected at collision energies ∼1−20 eV, corresponding to proton transfer to form HF + CH2Cl- and chlorine abstraction to form CH3 + FCl-. The threshold energy for the proton-transfer reaction is E 0 = 97 ± 9 kJ/mol, which yields Δacid H 298(CH3Cl) ≤ 1653 ± 9 kJ/mol and EA0(CH2Cl) ≥ 0.77 ± 0.14 eV. The threshold energy for the chlorine abstraction reaction to form FCl- is E 0 = 170 ± 40 kJ/mol, which yields EA0(FCl) ≥ 2.6 ± 0.4 eV. Potential energy surfaces for the three reaction paths are calculated using the coupled cluster and density functional theory methods at the CCSD(T)/aug-cc-pVDZ and B3LYP/aug-cc-pVDZ levels. Geometry optimizations of stationary points along the surfaces show that a hydrogen-bonded F-···H−CH2Cl complex is 5 kJ/mol lower in energy than the C 3 v F-···CH3Cl complex. An additional feature observed in the Cl- reaction cross section at collision energies above 2 eV is attributed to further dissociation of CH2Cl- and FCl- products.

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Section: Discussionsupporting

confidence: 81%

supporting

confidence: 75%

Section: Discussionmentioning

confidence: 62%

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Dynamics of the Gas-Phase Reactions of Fluoride Ions with Chloromethane

and

Ervin

2001

J. Phys. Chem. A

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“…The latter case would not formally produce a biexponential decay; however, the fast disappearance of 3 IC and the subsequent formation and decay of another transient species could be indistinguishable from a biexponential decay with our data. In particular, Cl 2 – forms in transient spectroscopy experiments on bulk aqueous IC/NaCl solutions on the timescale of our experiment according to the mechanism The radical, Cl 2 – , is a potential photoemitter, because it absorbs strongly at 355 nm and has a low ionization potential . The association of Cl atoms and Cl – is fast (7.8 × 10 9 M –1 s –1 ), so the appearance of Cl 2 – would coincide with the decay of 3 IC.…”

Section: Resultsmentioning

confidence: 77%

“…The radical, Cl 2 − , is a potential photoemitter, because it absorbs strongly at 355 nm 56 and has a low ionization potential. 57 The association of Cl atoms and Cl − is fast (7.8 × 10 9 M −1 s −1 ), 58 so the appearance of Cl 2 − would coincide with the decay of 3 IC. In this model of the data, the fast decay corresponds to the decay of 3 IC and the slow decay to the disappearance of Cl 2 − .…”

Section: ■ Resultsmentioning

confidence: 99%

Lifetime of Triplet Photosensitizers in Aerosol Using Time-Resolved Photoelectric Activity

Woods

Harris

Leiter

et al. 2020

ACS Earth Space Chem.

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Time-resolved photoelectric activity of aerosol (TPEAA) experiments measure the kinetics of photochemically initiated reactions near the surface of aerosol particles. In the demonstration presented here, TPEAA experiments monitor the evolution of excited triplet states, which are key intermediates in the photochemical formation of secondary organic aerosol (SOA). One example is the decay of the triplet excited state of imidazole-2-carboxaldehyde (IC) in aqueous NaCl aerosol particles. The decay of the triplet IC shows two distinct timescales, indicative of two populations of IC in the particles: aqueous and pure IC. The lifetime in the pure-IC phase is less than 20 ns, and the lifetime associated with aqueous IC is limited by reaction with chloride ions (k = 5.6 × 105 M–1 s–1). The results demonstrate how phase separation in aerosol particles can control reaction pathways and kinetics. In another example, TPEAA monitors the decay of the triplet anthraquinone-2-sulfonate (AQ2S) anion in aqueous NaCl aerosol. The AQ2S triplet reacts with water (k′ = 8.7 × 106 s–1) to produce adduct species. In this case, tuning the wavelength of the photoemission laser permits the preferential observation of the triplet or a combination of the AQ2S triplet and the water adduct. These results bridge a gap between aerosol phase measurements, which are normally steady-state and bulk-phase transient absorption measurements, which typically probe homogeneous phases.

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Collisional Ionization

Lacmann¹

1980

Advances in Chemical Physics

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Chemiionization in alkali-halogen reactions: Evidence for ion formation by alkali dimers

Cited by 30 publications

References 10 publications

Dynamics of the Gas-Phase Reactions of Fluoride Ions with Chloromethane

Dynamics of the Gas-Phase Reactions of Fluoride Ions with Chloromethane

Lifetime of Triplet Photosensitizers in Aerosol Using Time-Resolved Photoelectric Activity

Collisional Ionization

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