Dissociative recombination of protonated methanol

Geppert, Wolf D.; Hamberg, Mathias; Thomas, Richard; Österdahl, Fabian; Hellberg, F.; Zhaunerchyk, Vitali; Ehlerding, Anneli; Millar, T. J.; Roberts, H.; Semaniak, J.; Ugglas, M. af; Källberg, A.; Simonsson, Ansgar; Kaminska, M.; Larsson, Mats

doi:10.1039/b516010c

Cited by 204 publications

(194 citation statements)

References 34 publications

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“…Although methyl formate and dimethyl ether were hitherto assumed to be formed from their protonated ions via DR, this pathway could be expected as having equally low branching fraction as in the case of protonated methanol (Geppert et al 2006), where DR is dominated by three-body break-up channels and only 3% of the reactions leads to the unprotonated species (6% for the fully deuterated isotopologue). Such behaviour is not unique and has been observed in many H-rich ions, e.g.…”

Section: Introductionmentioning

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

A&A

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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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Section: Introductionmentioning

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

A&A

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“…Gasphase production of methyl formate, a molecule ubiquitous in hot-core spectra, appears prohibitively slow (Horn et al 2004), pointing to an efficient alternative. Additionally, the dissociative recombination of large organic molecular ions with electrons, which is typically the final step in the gas-phase synthesis of complex molecules, appears strongly to favor the fragmentation of complex structure (Geppert et al 2006). …”

Section: Introductionmentioning

confidence: 99%

Increased complexity in interstellar chemistry: detection and chemical modeling of ethyl formate andn-propyl cyanide in Sagittarius B2(N)

Беллоче

Garrod

Müller

et al. 2009

A&A

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Context. In recent years, organic molecules of increasing complexity have been found toward the prolific Galactic center source Sagittarius B2. Aims. We wish to explore the degree of complexity that the interstellar chemistry can reach in star-forming regions. Methods. We carried out a complete line survey of the hot cores Sgr B2(N) and (M) with the IRAM 30 m telescope in the 3 mm range, plus partial surveys at 2 and 1.3 mm. We analyzed this spectral survey in the local thermodynamical equilibrium approximation. We modeled the emission of all known molecules simultaneously, which allows us to search for less abundant, more complex molecules. We compared the derived column densities with the predictions of a coupled gas-phase and grain-surface chemical code.Results. We report the first detection in space of ethyl formate (C 2 H 5 OCHO) and n-propyl cyanide (C 3 H 7 CN) toward Sgr B2(N). The detection of n-propyl cyanide is based on refined spectroscopic parameters derived from combined analyses of available laboratory spectroscopic data. For each molecule, we identified spectral features at the predicted frequencies having intensities compatible with a unique rotation temperature. For an assumed source size of 3 , our modeling yields a column density of 5.4 × 10 16 cm −2 , a temperature of 100 K, and a linewidth of 7 km s −1 for ethyl formate. n-Propyl cyanide is detected with two velocity components having column densities of 1.5 × 10 16 cm −2 and 6.6 × 10 15 cm −2 , respectively, for a source size of 3 , a temperature of 150 K, and a linewidth of 7 km s −1 . The abundances of ethyl formate and n-propyl cyanide relative to H 2 are estimated to be 3.6 × 10 −9 and 1.0 × 10 −9 , respectively. We derived column density ratios of 0.8/15/1 for the related species t-HCOOH/CH 3 OCHO/C 2 H 5 OCHO and 108/80/1 for CH 3 CN/C 2 H 5 CN/C 3 H 7 CN. Our chemical modeling reproduces these ratios reasonably well. It suggests that the sequential, piecewise construction of ethyl and n-propyl cyanide from their constituent functional groups on the grain surfaces is their most likely formation route. Ethyl formate is primarily formed on the grains by adding CH 3 to functional-group radicals derived from methyl formate, although ethanol may also be a precursor. Conclusions. The detection in Sgr B2(N) of the next stage of complexity in two classes of complex molecule, esters and alkyl cyanides, suggests that greater complexity in other classes of molecule may be present in the interstellar medium.

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“…The signal from the detector was monitored by a single channel analyzer, selecting signals only when all the fragments reach the detector simultaneously, and thereafter recorded by a multichannel scaler, yielding the number of counts vs. storage time and, therefore, at a given relative kinetic energy. After correction for space charge, toroidal effects, and the energy spread of the electrons (see, e. g., Geppert et al 2006 for details), the cross sections of the investigated DR reactions could be determined. Under assumption of a Maxwell-Boltzmann distribution of kinetic energies of the reactants, their thermal rate constants were calculated.…”

Section: Resultsmentioning

confidence: 99%

Formation of biomolecule precursors in space?

Geppert¹,

Vigren²,

Hamberg³

et al. 2008

Proc. IAU

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Abstract. The possibility of an extraterrestrial origin of biomolecule building blocks has been a subject of intense discussions for many years. The detection of amino acids in meteorites opens the possibility of a delivery of biomolecules synthesized in the interstellar medium or star-forming regions to the primeval Earth. Whereas it can be doubted if more complex species like amino acids can survive the strong UV radiation in the early Solar System, this does not necessary hold for more primitive precursor molecules like nitriles. These compounds can also be synthesized very efficiently in methane-nitrogen dominated atmospheres like the one present on Titan and the early ages of Earth. This Contribution focuses on the formation and degradation processes of nitriles in interstellar clouds and planetary atmospheres and on their possible role in the generation of biomolecules.

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Dissociative recombination of protonated methanol

Cited by 204 publications

References 34 publications

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

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

Increased complexity in interstellar chemistry: detection and chemical modeling of ethyl formate andn-propyl cyanide in Sagittarius B2(N)

Formation of biomolecule precursors in space?

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Dissociative recombination of protonated methanol

Cited by 204 publications

References 34 publications

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

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

Increased complexity in interstellar chemistry: detection and chemical modeling of ethyl formate andn-propyl cyanide in Sagittarius B2(N)

Formation of biomolecule precursors in space?

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

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