A combined crossed molecular beams and theoretical study of the reaction CN+C2H4

Balucani, Nadia; Leonori, Francesca; Petrucci, Raffaele; Wang, Xingan; Casavecchia, Piergiorgio; Skouteris, Dimitrios; Albernaz, Alessandra F.; Gargano, Ricardo

doi:10.1016/j.chemphys.2014.12.014

Cited by 19 publications

(19 citation statements)

References 49 publications

(77 reference statements)

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“…We obtained rate constants via a combination of capture theory and RRKM calculations, using the same code we developed and described in previous papers (Leonori et al 2009(Leonori et al , 2013Balucani et al 2015). The rate constant for the formation of the initial intermediate is calculated using capture theory as detailed in Vazart et al (2015).…”

Section: Kinetics Calculationsmentioning

confidence: 99%

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Skouteris

Balucani

Falcinelli

et al. 2015

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Aims. We theoretically investigated the dimerization of methanimine, CH 2 =NH, a process that has been invoked to explain the formation of haze in the atmosphere of Titan and nitrogen organic compounds in interstellar/cometary ice analogs. Methods. We used density functional theory to characterize the minima and transition states of the investigated processes, while we computed the energetics with the more accurate coupled cluster method. We then obtained rate coefficients via combination of capture theory and statistical calculations. Results. The process involving two neutral molecules is characterized by significant energy barriers and cannot occur under the low temperature conditions of Titan or interstellar/cometary ices unless an external energy source is provided. On the contrary, the processes involving one molecule of either ionized or protonated methanimine are barrierless reactions and can therefore contribute to the formation of larger ions. In particular, the reaction involving ionized methanimine can also be efficient in the very low temperature conditions of the interstellar medium, leading to products of general formula C 2 N 2 H + .Conclusions. The present work suggests that polymerization of methanimine is not an efficient process in space unless an ionization/protonation or a significant energy source is available.

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Section: Kinetics Calculationsmentioning

confidence: 99%

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Skouteris

Balucani

Falcinelli

et al. 2015

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“…The reaction has been found to be very fast also at the very low temperatures which are typical of interstellar clouds and Titan with a rate coefficient of the order of 10 –10 cm 3 mol –1 s –1 according to CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme) experiments. 30 This reaction was also explored by means of the crossed molecular beam (CMB) method with mass-spectrometric (MS) detection 31 − 35 and characterized by electronic structure calculations of the potential energy surface (PES). 35 , 36 The CMB-MS experiments demonstrated that the channel leading to the formation of cyanoethene and atomic hydrogen is the dominant pathway, even though at high collision energies the isocyanoethene isomer can be formed with a very small yield.…”

Section: Introductionmentioning

confidence: 99%

Unsaturated Dinitriles Formation Routes in Extraterrestrial Environments: A Combined Experimental and Theoretical Investigation of the Reaction between Cyano Radicals and Cyanoethene (C₂H₃CN)

et al. 2022

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The reaction between cyano radicals (CN, X 2 Σ + ) and cyanoethene (C 2 H 3 CN) has been investigated by a combined approach coupling crossed molecular beam (CMB) experiments with mass spectrometric detection and time-of-flight analysis at a collision energy of 44.6 kJ mol –1 and electronic structure calculations to determine the relevant potential energy surface. The experimental results can be interpreted by assuming the occurrence of a dominant reaction pathway leading to the two but-2-enedinitrile (1,2-dicyanothene) isomers ( E - and Z -NC–CH=CH–CN) in a H-displacement channel and, to a much minor extent, to 1,1-dicyanoethene, CH 2 C(CN) 2 . In order to derive the product branching ratios under the conditions of the CMB experiments and at colder temperatures, including those relevant to Titan and to cold interstellar clouds, we have carried out RRKM statistical calculations using the relevant potential energy surface of the investigated reaction. We have also estimated the rate coefficient at very low temperatures by employing a semiempirical method for the treatment of long-range interactions. The reaction has been found to be barrierless and fast also under the low temperature conditions of cold interstellar clouds and the atmosphere of Titan. Astrophysical implications and comparison with literature data are also presented. On the basis of the present work, 1,2-dicyanothene and 1,1-dicyanothene are excellent candidates for the search of dinitriles in the interstellar medium.

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“…This holds in particular for bimolecular reactions between diatomic radicals and small hydrocarbons. Bimolecular reactions involving diatomic radicals such as boron monoxide (BO), [28][29][30][31][32][33][34][35] boron monosulfide (BS), [36][37] methylidyne (CH/CD), [38][39][40][41][42][43][44][45] cyano (CN), 32,[46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] dicarbon (C 2 ), 57,[61][62][63][64][65][66][67][68][69][70][71][72][73][74] hydroxyl (OH), [75]…”

Section: Introductionmentioning

confidence: 99%

“…Acetylene (HCCH) 32,48,56,[60][61] Ethylene (H2CCH2) 32, 56, 60-61 Methylacetylene (CH3CCH) 48,56,[60][61] Allene (CH2CCH2) 56,[60][61] Propylene(CH3CCH2) 46 Diacetylene (HCCCCH) 48,61 Vinylacetylene (HCCC2H3) 59 1,3-Butadiene (CH2CHCHCH2) 47 2-Butyne (CH3CCCH3) 56,60 Benzene (C6H6) 56,[60][61] Phenylacetylene (C6H5CCH) 58 Styrene (C6H5C2H3) Acetylene (HCCH) 54,57 Ethylene (H2CCH2) 53 61 Vinylacetylene (CH2CHCCH) 69 1,3-Butadiene (CH2CHCHCH2) 70 1,2-Butadiene (CH3CHCCH2) 65 1-Butyne(CH3CH2CCH) 65 2-Butyne(CH3CCCH3) 65 1,3-Pentadiene (CH3CHCHCHCH2) 66 Isoprene (CH2C(CH3)CHCH2) 67 Benzene(C6H6) 61,63 Hydrogen Sulfide(H2S) 62 Hydrogen Cyanide(HCN) 68 Acetylene (HCCH) [73][74]…”

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A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)

et al. 2016

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The bimolecular gas-phase reactions of the ground-state silylidyne radical (SiH; X(2)Π) with methylacetylene (CH3CCH; X(1)A1) and D4-methylacetylene (CD3CCD; X(1)A1) were explored at collision energies of 30 kJ mol(-1) under single-collision conditions exploiting the crossed molecular beam technique and complemented by electronic structure calculations. These studies reveal that the reactions follow indirect scattering dynamics, have no entrance barriers, and are initiated by the addition of the silylidyne radical to the carbon-carbon triple bond of the methylacetylene molecule either to one carbon atom (C1; [i1]/[i2]) or to both carbon atoms concurrently (C1-C2; [i3]). The collision complexes [i1]/[i2] eventually isomerize via ring-closure to the c-SiC3H5 doublet radical intermediate [i3], which is identified as the decomposing reaction intermediate. The hydrogen atom is emitted almost perpendicularly to the rotational plane of the fragmenting complex resulting in a sideways scattering dynamics with the reaction being overall exoergic by -12 ± 11 kJ mol(-1) (experimental) and -1 ± 3 kJ mol(-1) (computational) to form the cyclic 2-methyl-1-silacycloprop-2-enylidene molecule (c-SiC3H4; p1). In line with computational data, experiments of silylidyne with D4-methylacetylene (CD3CCD; X(1)A1) depict that the hydrogen is emitted solely from the silylidyne moiety but not from methylacetylene. The dynamics are compared to those of the related D1-silylidyne (SiD; X(2)Π)-acetylene (HCCH; X(1)Σg(+)) reaction studied previously in our group, and from there, we discovered that the methyl group acts primarily as a spectator in the title reaction. The formation of 2-methyl-1-silacycloprop-2-enylidene under single-collision conditions via a bimolecular gas-phase reaction augments our knowledge of the hitherto poorly understood silylidyne (SiH; X(2)Π) radical reactions with small hydrocarbon molecules leading to the synthesis of organosilicon molecules in cold molecular clouds and in carbon-rich circumstellar envelopes.

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A combined crossed molecular beams and theoretical study of the reaction CN+C2H4

Cited by 19 publications

References 49 publications

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Unsaturated Dinitriles Formation Routes in Extraterrestrial Environments: A Combined Experimental and Theoretical Investigation of the Reaction between Cyano Radicals and Cyanoethene (C₂H₃CN)

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)

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A combined crossed molecular beams and theoretical study of the reaction CN+C2H4

Cited by 19 publications

References 49 publications

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Dimerization of methanimine and its charged species in the atmosphere of Titan and interstellar/cometary ice analogs

Unsaturated Dinitriles Formation Routes in Extraterrestrial Environments: A Combined Experimental and Theoretical Investigation of the Reaction between Cyano Radicals and Cyanoethene (C2H3CN)

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X2Π) with Methylacetylene (CH3CCH; X1A1) and D4-Methylacetylene (CD3CCD; X1A1)

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Unsaturated Dinitriles Formation Routes in Extraterrestrial Environments: A Combined Experimental and Theoretical Investigation of the Reaction between Cyano Radicals and Cyanoethene (C₂H₃CN)

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)