Rate constants and branching ratios for the dissociative recombination of C3D7+ and C4D9+

Larsson, Mats; Ehlerding, Anneli; Geppert, Wolf D.; Hellberg, F.; Kalhori, S.; Thomas, Richard; Djurić, N.; Österdahl, Fabian; Angelova, G. V.; Semaniak, J.; Novotny, Steffen; Arnold, Susan T.; Viggiano, Albert A.

doi:10.1063/1.1872839

Cited by 17 publications

(14 citation statements)

References 20 publications

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“…That would make it possible to fit Gaussian functions to each mass peak but due to the insufficient resolution this could not be achieved. In most cases, fully deuterated substances yield similar to identical branching fractions (Jensen et al 2000;Neau et al 2000;Geppert et al 2006), although exceptions exist (Hamberg et al 2007;Larsson et al 2005). …”

Section: Implications Of the Branching Fractions Resultsmentioning

confidence: 99%

Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Hamberg

Zhaunerchyk

Vigren

et al. 2010

A&A

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Aims. We determine branching fractions, cross sections and thermal rate constants for the dissociative recombination of CD 3 CDOD + and CH 3 CH 2 OH + 2 at the low relative kinetic energies encountered in the interstellar medium. Methods. The experiments were carried out by merging an ion and electron beam at the heavy ion storage ring CRYRING, Stockholm, Sweden.Results. Break-up of the CCO structure into three heavy fragments is not found for either of the ions. Instead the CCO structure is retained in 23 ± 3% of the DR reactions of CD 3 CDOD + and 7 ± 3% in the DR of CH 3 CH 2 OH + 2 , whereas rupture into two heavy fragments occurs in 77 ± 3% and 93 ± 3% of the DR events of the respective ions. The measured cross sections were fitted between 1-200 meV yielding the following thermal rate constants and cross-section dependencies on the relative kinetic energy:

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Section: Implications Of the Branching Fractions Resultsmentioning

confidence: 99%

Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Hamberg

Zhaunerchyk

Vigren

et al. 2010

A&A

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“…Jensen et al (2000); Neau et al (2000); Geppert et al (2006). But exceptions exist (Hamberg et al 2007;Larsson et al 2005), which possibly are due to easier tunneling of hydrogen atoms through exit barriers.…”

Section: Isotopic Effectmentioning

confidence: 99%

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD₃OCD$_{2}^{+}$ and (CD₃)₂OD⁺

Hamberg¹,

Österdahl²,

Thomas³

et al. 2010

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Aims. Determination of branching fractions, cross sections and thermal rate coefficients for the dissociative recombination of CD 3 OCD 2 + (0-0.3 eV) and (CD 3 ) 2 OD + (0-0.2 eV) at the low relative kinetic energies encountered in the interstellar medium. Methods. The measurements were carried out using merged electron and ion beams at the CRYRING storage ring, Stockholm, Sweden.Results. For (CD 3 ) 2 OD + we have experimentally determined the branching fraction for ejection of a single hydrogen atom in the DR process to be maximally 7% whereas 49% of the reactions involve the break up of the COC chain into two heavy fragments and 44% ruptures both C-O bonds. The DR of CD 3 OCD 2 + is dominated by fragmentation of the COC chain into two heavy fragments. The measured thermal rate constants and cross sections are k(T ) = 1.7 ± 0.5 × 10 −6 (T/300) −0.77±0.01 cm 3 s −1 , σ = 1.2 ± 0.4 × 10 −15 (E cm [eV]) −1.27±0.01 cm 2 and k(T ) = 1.7 ± 0.6 × 10 −6 (T/300) −0.70 ± 0.02 cm 3 s −1 , σ = 1.7 ± 0.6 × 10 −15 (E cm [eV]) −1.20±0.02 cm 2 for CD 3 OCD 2 + and (CD 3 ) 2 OD + , respectively.

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“…De La Haye et al (2008) suggest that dissociative recombination of C 3 H + 7 ions will provide another important high-altitude source of C 2 H 6 on Titan (and by analogy Jupiter); however, Larsson et al (2005) have found that the ethane formation pathway from C 3 H + 7 electron recombination (i.e., C 3 H + 7 + e − −→ C 2 H 6 + CH) is negligible, such that the ion-neutral reactions 10 and 11 would be more effective.…”

Section: Hydrocarbonsmentioning

confidence: 99%

Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

Sinclair

Orton

Greathouse

et al. 2017

Icarus

107

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Auroral processes are evident in Jupiter's polar atmosphere over a large range in wavelength (X-ray to radio). In particular, previous observations in the mid-infrared (5 to 15 µm) have shown enhanced emission from CH 4 , C 2 H 2 and C 2 H 4 and further stratospheric hydrocarbon species in spatial regions coincident with auroral processes observed at other wavelengths. These regions, described as auroral-related hotspots, observed at approximately 160• W to 200• W (System III) at high-northern latitudes and 330• W to 80• W at high-southern latitudes, indicate that auroral processes modify the thermal structure and composition of the neutral atmosphere. However, previous studies have struggled to differentiate whether the aforementioned enhanced emission is a result of either temperature changes and/or changes in the concentration of the emitting species. We attempt to address this degeneracy in this work by performing a retrieval analysis of Voyager 1-IRIS spectra (acquired in 1979) and Cassini-CIRS spectra (acquired in 2000/2001) of Jupiter. Retrievals of the vertical temperature profile in Cassini-CIRS spectra covering the auroral-related hotspots indicate the presence of two discrete vertical regions of heating at the 1-mbar level and at pressures of 10-µbar and lower. For example, in Cassini-CIRS 2.5 cm −1 'MIRMAP' spectra at 70• N (planetographic) 180• W (centred on the auroral oval), we find temperatures at the 1-mbar level and 10-µbar levels are enhanced by 15.3 ± 5.2 K and 29.6 ± 15.0 K respectively, in comparison to results at 70• N, 60• W in the same dataset. High temperatures at 10-µbar and lower pressures were considered indicative of joule heating, ion and/or electron precipitation, ion-drag and energy released form exothermic ion-chemistry. However, we conclude that the heating at the 1-mbar level is the result of either a layer of aurorally-produced haze particles, which are heated by incident sunlight and/or adiabatic heating by downwelling within the auroral hot-spot region. The former mechanism would be consistent with the vertical profiles of polycyclic aromatic hydrocarbons (PAHs) and haze particles predicted in auroral-chemistry models (Wong et al., 2000(Wong et al., , 2003. Retrievals of C 2 H 2 and C 2 H 6 were also performed and indicate C 2 H 2 is enriched but C 2 H 6 is depleted in auroral regions relative to quiescent regions. For example, using CIRS ∆ν = 2.5 cm −1 spectra, we determined that C 2 H 2 at 0.98 mbar increases by 175.3 ± 89.3 ppbv while C 2 H 6 at 4.7 mbar decreases by 0.86 ± 0.59 ppmv in comparing results at 70• N, 180• W and 70• N, 60• W. These results represent a mean of values retrieved from different initial assumptions and thus we believe they are robust. We believe these contrasts in C 2 H 2 and C 2 H 6 between auroral and quiescent regions can be explained by a coupling of auroral-driven chemistry and horizontal advection. Ion-neutral and electron recombination chemistry in the auroral region enriches all C 2 hydrocarbons but in particular, the unsaturated ...

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Rate constants and branching ratios for the dissociative recombination of C3D7+ and C4D9+

Cited by 17 publications

References 20 publications

Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD₃OCD$_{2}^{+}$ and (CD₃)₂OD⁺

Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

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Rate constants and branching ratios for the dissociative recombination of C3D7+ and C4D9+

Cited by 17 publications

References 20 publications

Experimental studies of the dissociative recombination of CD3CDOD+and CH3CH2OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination of CD3CDOD+and CH3CH2OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD3OCD$_{2}^{+}$ and (CD3)2OD+

Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

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Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination of CD₃CDOD⁺and CH₃CH₂OH$_{2}^+$Unknown node mtable found in MathML fragment.

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD₃OCD$_{2}^{+}$ and (CD₃)₂OD⁺