The production of HCN dimer and more complex oligomers   in 
 dense interstellar clouds

Smith, Ian W. M.; Talbi, Dahbia; Herbst, Eric

doi:10.1051/0004-6361:20010126

Cited by 61 publications

(48 citation statements)

References 12 publications

(19 reference statements)

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“….HCN, while the lowest chemically bound (i.e. not H-bond complexed) C 2 H 2 N 2 neutral has the structure HNC(H)CN [49]. No literature value of the enthalpy of formation is available for C 2 H 2 N þ 2 .…”

Section: Pyrimidine (C 4 H 4 N 2 )mentioning

confidence: 99%

“…Speculation has been made on the possible formation of adenine in the ISM by successive condensation reactions of HCN [85] but this proposal has been contested by Smith et al [86]. A very recent computational study of mechanisms of prebiotic pyrimidine-ring formation of monocyclic HCN-pentamers, with application to adenine synthesis is space, has been carried out by Glaser et al [87].…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

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VUV photophysics and dissociative photoionization of pyrimidine, purine, imidazole and benzimidazole in the 7–18eV photon energy range

et al. 2008

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Section: Pyrimidine (C 4 H 4 N 2 )mentioning

confidence: 99%

Section: Astrophysical Implicationsmentioning

confidence: 99%

VUV photophysics and dissociative photoionization of pyrimidine, purine, imidazole and benzimidazole in the 7–18eV photon energy range

et al. 2008

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“…However, Chakraborti & Chakraborti (2000) proposed on the basis of modeling calculations that DNA bases can be produced by gas phase reactions in dense interstellar clouds. This view was strongly contradicted by Smith et al (2001). On the basis of quantum chemical and kinetic techniques, they showed that reaction between two HCN molecules under interstellar conditions cannot efficiently lead to a dimer (H 2 C 2 N 2 ) and hence it is impossible to synthesize detectable abundances of the HCN oligomer adenine (H 5 N 5 C 5 ) in the interstellar medium via successive A&A 528, A129 (2011) neutral-neutral reactions between HCN and its dimer, trimer and tetramer.…”

Section: Introductionmentioning

confidence: 99%

Quantum chemical study of a new reaction pathway for the adenine formation in the interstellar space

Gupta

Tandon

Rawat

et al. 2011

A&A

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Gas phase chemistry in the cold interstellar clouds is dominated by ion-molecule and radical-radical interactions, though some neutralneutral reactions are also barrier-free and efficient at cold temperatures. It has been suggested that it is impossible to synthesize detectable abundances of the pre-biotic HCN oligomer adenine (H 5 C 5 N 5 ) in the interstellar medium via successive neutral-neutral reactions. We attempted therefore to use quantum chemical techniques to explore if adenine can possibly form in the interstellar space by radical-radical and radical-molecule interaction schemes, both in the gas phase and in the grains. We report results of ab initio calculations for the formation of adenine starting from some of the simple neutral molecules and radicals detected in the interstellar space. The reaction path is found to be totally exothermic and barrier free, which increases the probability of occurrence in the cold interstellar clouds (10−50 K). We also estimated the reaction rates.

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“…HCN is known to easily polymerize in the condensed phase, forming many species of prebiotic interest (Matthews 1995) and, therefore, HCN was considered to polymerize also in the interstellar medium (Chakrabarti & Chakrabarti 2000). However, Smith et al (2001) proved that the dimerization process in the gas phase is characterized by a very high barrier, thus precluding any significant role of HCN dimerization in space.…”

Section: Introductionmentioning

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

A&A

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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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The production of HCN dimer and more complex oligomers in dense interstellar clouds

Cited by 61 publications

References 12 publications

VUV photophysics and dissociative photoionization of pyrimidine, purine, imidazole and benzimidazole in the 7–18eV photon energy range

VUV photophysics and dissociative photoionization of pyrimidine, purine, imidazole and benzimidazole in the 7–18eV photon energy range

Quantum chemical study of a new reaction pathway for the adenine formation in the interstellar space

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

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