Microwave Detection of Interstellar Formamide

Rubin, R. H.; Swenson, George W.; Benson, Richard C.; Tigelaar, H. L.; Flygare, W. H.

doi:10.1086/180810

Cited by 220 publications

(167 citation statements)

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“…In the same way, it has been shown that formamide (Rubin et al 1971), acetamide (Hollis et al 2006), and aminoacetonitrile (Belloche et al 2008) were the most stable species of their generic families . The relatively high abundance of the isocyanide derivatives with respect to their more stable cyano counterparts (in view of the large bonding energy differences) has been ascribed to non-thermal processes in different interstellar environments (Remijan et al 2005).…”

Section: Introductionmentioning

confidence: 73%

About the detectability of glycine in the interstellar medium

Lattelais

Pauzat

Pilmé

et al. 2011

A&A

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Context. Glycine, the simplest of aminoacids, has been found in several carbonaceous meteorites. It remains unclear, however, wether glycine is formed in the interstellar medium (ISM) and therefore available everywhere in the Universe. For this reason, radioastronomers have searched for many years unsuccessfully to detect glycine in the ISM. Aims. We provide possible guidelines to optimize the return of these searches. Since, for most of the species observed so far in the ISM, the most abundant isomer of a given generic chemical formula is the most stable one (minimum energy principle (MEP)), we assess whether neutral glycine is the best molecule to search for or whether one of its isomers/conformers or ionic, protonated, or zwitterionic derivatives would have a higher probability of being detected. Methods. The question of the relative stability of these different species is addressed by means of quantum density functional theory (DFT) simulations within the hybrid B3LYP formalism. Each fully optimized structure is verified as a stationary point by means of a vibrational analysis. A comprehensive screening of 32 isomers/conformers of the C 2 H 5 O 2 N chemical formula (neutral, negative, and positive ions together with the corresponding protonated species and the possible zwitterionic structures) is carried out. In the sensitive case of the neutral compounds, more accurate relative energies were obtained by means of high level post Hartree-Fock coupled cluster calculations with large basis sets (CCSD(T)/cc-pVQZ). Results. We find that neutral glycine is not the most stable isomer and, therefore, probably not the most abundant one, which might explain why it has escaped detection so far. We find instead that N-methyl carbamic acid and methyl carbamate are the two most stable isomers and, therefore, probably the two most abundant ones. Among the non-neutral forms, we found that glycine is the most stable isomer only if protonated or zwitterionic if present in interstellar ices. Conclusions. Assuming that MEP can be applied to optimize our search for glycine, our conclusion is that this search will remain extremely difficult with the present instruments and we propose searching instead for other examples among the most stable isomers.

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Section: Introductionmentioning

confidence: 73%

About the detectability of glycine in the interstellar medium

Lattelais

Pauzat

Pilmé

et al. 2011

A&A

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“…The identification of more than 80 amino acids in meteorites, such as Murchison (Cooper et al 1992), is a positive clue about the presence of amino acids in space. In contrast, molecules with a peptide bond (NH-C=O), such as formamide (Rubin et al 1971) and acetamide (Hollis et al 2006), have been detected in interstellar clouds, and Halfen et al (2011) recently highlighted their importance as prototypes for peptide bond formation. Because of these compounds' relatively large abundance, Halfen et al suggest that they could be a possible source of larger peptide molecules that do not involve amino acids.…”

Section: Introductionmentioning

confidence: 99%

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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“…Two emission lines with 14N nuclear quadrupole hyperfine splitting have been found in each case, corresponding to the two lowest asymmetry doublets, 110-111 at a wavelength of 19 cm (palmer et al 1971) and 211-212 at 6 cm (Rubin et al 1971). The present search concerns the transition 312-313, which is the next highest asymmetry doublet in this series.…”

Section: Formamide (Nh 2 Cho)mentioning

confidence: 66%

A Search for Interstellar Molecular Lines in the Frequency Range 8·6 to 9·2 GHz

Batchelor¹,

Brooks

Godfrey³

et al. 1973

Aust. J. Phys.

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An unsuccessful search has been made in the directions of Sagittarius B2, Sagittarius A, and Orion A for molecular lines of formyl, pyridine, formaldehyde, acrolein, and formamide in the frequency range 8·6 to 9·2 GHz. The failure to detect the formyl line in particular provides evidence about the possible modes of formation of interstellar formaldehyde.A search in the frequency range 8·6 to 9·2 GHz has failed to detect lines of formyl (HCO), pyridine (C5H5N), formaldehyde (HzCO), acrolein (CHzCHCHO), or formamide (NHzCHO) in the directions of the molecular sources Sagittarius B2, Sagittarius A (NH 3 ), and Orion A. The observations were carried out in November 1971 using the Parkes 64 m radio telescope. At this frequency the antenna has an aperture efficiency of 38 % and a beamwidth of 2' . 5 arc. The receiver consisted of a tunable cryogenic parametric amplifier (Kerr 1972) giving a system temperature of '" 180 K, followed by a bank of 64 filters each of 100 kHz bandwidth and with approximately Gaussian passbands (Batchelor et al. 1969). The filter outputs were connected via a set of integrate-and-hold circuits to a multiplexer and on-line computer. The computer controlled the receiver, switching it between the feed horn and a cryogenic termination and switching on the calibration noise source at preselected intervals. In addition it carried out the synchronous detection, normalization, and accumulation of data.The telescope was positioned on Sgr B2 and Orion A by maximizing the continuum signal. On Sgr A (NH3) the telescope was pointed at the nominal position using corrections determined for Sgr B2. Pointing was always within 0' . 3 arc of the nominal position. Observations were made by integrating for 20 min at the line frequency while following the source. A reference spectrum was then obtained on a blank region of sky chosen so that the telescope traversed the same range of zenith and azimuth angles. Such source and reference profiles were accumulated by the computer for a total of several hours, and their difference was taken.The molecules and the transitions unsuccessfully searched for are listed in Table 1, together with the sources observed for each transition and the peak-to-peak, channelto-channel noise expressed as antenna temperature. The noise was between 0·07 and 0·11 K for each observation except that for formamide in OrionA. In this case the

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Microwave Detection of Interstellar Formamide

Cited by 220 publications

References 0 publications

About the detectability of glycine in the interstellar medium

About the detectability of glycine in the interstellar medium

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

A Search for Interstellar Molecular Lines in the Frequency Range 8·6 to 9·2 GHz

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