Detection of the Ammonium Ion in Space

Cernicharo, J.; Tercero, B.; Fuente, A.; Doménech, José Luis; Cueto, Maite; Carrasco, Esther; Herrero, Vı́ctor J.; Tanarro, Isabel; Marcelino, N.; Roueff, E.; Gérin, M.; Pearson, John C.

doi:10.1088/2041-8205/771/1/l10

Cited by 66 publications

(81 citation statements)

References 40 publications

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“…Among the selected species, NH + 4 (Cernicharo et al 2013), H 2 CO (Synder et al 1969), and HCOOH (Winnewisser & Churchwell 1975) were detected in interstellar space. The NH + 3 cation was not detected in space; however, the neutral molecule, NH 3 , was observed (Cheung et al 1968), and it can be easily ionized in interstellar conditions (IP = 10.07 eV; NIST Chemistry WebBook 2009).…”

Section: Thermodynamic Resultsmentioning

confidence: 98%

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

Redondo

Barrientos

Largo

2013

ApJ

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We study the viability of different gas-phase ion-molecule reactions that could produce precursors of formamide in the interstellar medium. We analyze different reactions between cations containing a nitrogen atom (NH + 3 , NH + 4 , NH 3 OH + , and NH 2 OH + ) and neutral molecules having one carbonyl group (H 2 CO and HCOOH). First, we report a theoretical estimation of the reaction enthalpies for the proposed processes. Second, for more favorable reactions, from a thermodynamic point of view, we perform a theoretical study of the potential energy surface. In particular, the more exothermic processes correspond to the reactions of ionized and protonated hydroxylamine with formaldehyde. In addition, a neutral-neutral reaction has also been considered. The analysis of the potential energy surfaces corresponding to these reactions shows that these processes present a net activation barrier and that they cannot be considered as a source of formamide in space.

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Section: Thermodynamic Resultsmentioning

confidence: 98%

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

Redondo

Barrientos

Largo

2013

ApJ

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“…Up to date, we performed a deep analysis of the data (15 papers have been already published): identifying more than 15 000 spectral features (Tercero et al 2010;, detecting new molecules in space (CH 3 COOCH 3 and g-CH 3 CH 2 OCOH in Tercero et al 2013; NH 3 D + in Cernicharo et al 2013; CH 3 CH 2 SH in Kolesniková et al 2014; also tentative detections of c-C 6 H 5 O in Kolesniková et al 2013 and upper limit calculations for the column density of non detected molecules −cis-CH 2 CHCH 2 CN and cis-CH 2 CHCH 2 NC− in Haykal et al 2013b) and several new isotopologues and Table 2. (1…”

Section: Observations Data Reduction and Overall Resultsmentioning

confidence: 99%

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

Haykal¹,

Carvajal²,

Tercero³

et al. 2014

A&A

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Context. An astronomical survey of interstellar molecular clouds needs a previous analysis of the spectra in the microwave and sub-mm energy range of organic molecules to be able to identify them. We obtained very accurate spectroscopic constants in a comprehensive laboratory analysis of rotational spectra. These constants can be used to predict the transitions frequencies very precisely that were not measured in the laboratory. Aims. We present the experimental study and its theoretical analysis for two 13 C-methyl formate isotopologues to detect these two isotopologues for the first time in their excited torsional states, which lie at 130 cm −1 (200 K) in Orion-KL. Methods. New spectra of HCOO 13 CH 3 ( 13 C 2 ) methyl formate were recorded with the mm-and submm-wave spectrometer in Lille from 50 to 940 GHz. A global fit for v t = 0 and 1 was accomplished with the BELGI program to reproduce the experimental spectra with greater accuracy. Results. We analysed 5728 and 2881 new lines for v t = 0 and 1 for HCOO 13 CH 3 . These new lines were globally fitted with 846 previously published lines for v t = 0. In consequence, 52 parameters of the RAM Hamiltonian were accurately determined and the value of the barrier height (V 3 = 369.93168(395) cm −1 ) was improved. We report the detection of the first excited torsional states (v t = 1) in Orion-KL for the 13 C 2 and 13 C 1 methyl formate based on the present analysis and previously published data. We provide column densities, isotopic abundances, and vibrational temperatures for these species. Conclusions. Following this work, accurate prediction can be provided. This permits detecting 135 features of the first excited torsional states of 13 C-methyl formate isotopologues in Orion-KL in the 80−280 GHz frequency range, without missing lines.

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“…There are, however, two important differences with oxygen : i) the carbon reservoir is CO and not methane, ii) carbon hydride radicals (CH, CH 2 , CH 3 ) and ions (CH + 3 ) initiate the organic chemistry and therefore play a pivotal role in the formation of a large fraction of the molecules present in the ISM. Another interesting property of the methylidyne radical, CH, is the linear scaling of its column density, deduced from the intensity of its Λ-doubling transitions at 3.3 GHz, with that of H 2 up to A V ∼ 3 mag (Mattila 1986;Chastain, Cotten & Magnani 2010). Although these lines are inverted, with negative excitation temperatures, their integrated intensity approximately scales with the CH column density (Liszt & Lucas 2002).…”

Section: Methane and Carbon Hydridesmentioning

confidence: 99%

“…Ground based spectra of nitrogen hydrides towards the protostellar core Barnard1b (T = 12 K, n H 2 = 10 5 cm −3 , N(H 2 ) = 10 23 cm −2 ) (adapted from Daniel et al 2013;Lis et al 2010b;Cernicharo et al 2013). Methane is best probed by infrared spectroscopy using either ground-based or space-born telescopes in the 8 µm region (Lacy et al 1991;Öberg et al 2008). Frozen methane has an abundance ∼ 5% that of water ice, supporting a formation process through sequential hydrogenation of carbon on grain surfaces.…”

Section: Figure 13mentioning

confidence: 99%

Interstellar Hydrides

Gérin

Neufeld

Goicoechea

2016

Annu. Rev. Astron. Astrophys.

128

171

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Interstellar hydrides -that is, molecules containing a single heavy element atom with one or more hydrogen atoms -were among the first molecules detected outside the solar system. They lie at the root of interstellar chemistry, being among the first species to form in initially-atomic gas, along with molecular hydrogen and its associated ions. Because the chemical pathways leading to the formation of interstellar hydrides are relatively simple, the analysis of the observed abundances is relatively straightforward and provides key information about the environments where hydrides are found. Recent years have seen rapid progress in our understanding of interstellar hydrides, thanks largely to far-IR and submillimeter observations performed with the Herschel Space Observatory. In this review, we will discuss observations of interstellar hydrides, along with the advanced modeling approaches that have been used to interpret them, and the unique information that has thereby been obtained.

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Detection of the Ammonium Ion in Space

Cited by 66 publications

References 40 publications

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate

Interstellar Hydrides

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Detection of the Ammonium Ion in Space

Cited by 66 publications

References 40 publications

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

Some Insights Into Formamide Formation Through Gas-Phase Reactions in the Interstellar Medium

THz spectroscopy and first ISM detection of excited torsional states of13C-methyl formate

Interstellar Hydrides

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THz spectroscopy and first ISM detection of excited torsional states of¹³C-methyl formate