Detection of a new carbon-chain molecule, CCO

Context. Carbon molecules and their 13C-isotopologues can be used to determine the 12C/13C abundance ratios in stellar and interstellar objects. C3 is a pure carbon chain molecule found in star-forming regions and in stellar shells of carbon-rich late-type stars. Latest laboratory data of 13C-isotopologues of C3 allow a selective search for the mono-substituted species 13CCC and C13CC based on accurate ro-vibrational frequencies. Aims. We aim to provide the first detection of the 13C-isotopologues 13CCC and C13CC in space and to derive the 12C/13C ratio of interstellar gas in the massive star-forming region SgrB2(M) near the Galactic Center. Methods. We used the heterodyne receivers GREAT and upGREAT on board SOFIA to search for the ro-vibrational transitions Q(2) and Q(4) of 13CCC and C13CC at 1.9 THz along the line of sight towards SgrB2(M). In addition, to determine the local excitation temperature, we analyzed data from nine ro-vibrational transitions of the main isotopologue CCC in the frequency range between 1.6 and 1.9 THz, which were taken from the Herschel Science Data Archive. Results. We report the first detection of the isotopologues 13CCC and C13CC. For both species, the ro-vibrational absorption lines Q(2) and Q(4) have been identified, primarily arising from the warm gas physically associated with the strong continuum source, SgrB2(M). From the available CCC ro-vibrational transitions, we derived a gas excitation temperature of Tex = 44.4+4.7−3.9 K, and a total column density of N(CCC) = 3.88+0.39−0.35 × 1015 cm−2. Assuming the excitation temperatures of C13CC and 13CCC to be the same as for CCC, we obtained column densities of the 13C-isotopologues of N(C13CC) = 2.1+0.9−0.6 × 1014 cm−2 and N(13CCC) = 2.4+1.2−0.8 × 1014 cm−2. The derived 12C/13C abundance ratio in the C3 molecules is 20.5 ± 4.2, which is in agreement with the elemental ratio of 20, typically observed in SgrB2(M). However, we find the N(13CCC)/N(C13CC) ratio to be 1.2 ± 0.1, which is shifted from the statistically expected value of two. We propose that the discrepant abundance ratio arises due to the lower zero-point energy of C13CC, which makes position-exchange reaction converting 13CCC to C13CC energetically favorable.

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Carbon-chain molecule survey toward four low-mass molecular outflow sources

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039110 ◽

2021 ◽

Vol 648 ◽

pp. A83

Author(s):

C. Zhang ◽

Y. Wu ◽

X.-C. Liu ◽

Mengyao Tang ◽

Di Li ◽

...

Keyword(s):

Radio Telescope ◽

Detection Rate ◽

Carbon Chain ◽

Chain Molecule ◽

Mass Star ◽

Star Forming ◽

Molecular Outflow ◽

Mass Outflow ◽

Low Mass ◽

Marginal Detection

We performed a carbon-chain molecule (CCM) survey toward four low-mass outflow sources, IRAS 04181+2655 (I04181), HH211, L1524, and L1598, using the 13.7 m telescope at the Purple Mountain Observatory (PMO) and the 65 m Tian Ma Radio telescope at the Shanghai Observatory. We observed the following hydrocarbons (C2H, C4H, c–C3H2), HC2n+1N (n = 1, 2), CnS (n = 2, 3), and SO, HNC, N2H+. Hydrocarbons and HC3N were detected in all the sources, except for L1598, which had a marginal detection of C4H and a non-detection of HC3N (J = 2–1). HC5N and CCCS were only detected in I04181 and L1524, whereas SO was only detected in HH211. L1598 exhibits the lowest detection rate of CCMs and is generally regarded to be lacking in CCMs source. The ratio of N(HC3N/N(N2H+)) increases with evolution in low-mass star-forming cores. I04181 and L1524 are carbon-chain-rich star-forming cores that may possibly be characterized by warm carbon-chain chemistry. In I04181 and L1524, the abundant CCCS can be explained by shocked carbon-chain chemistry. In HH211, the abundant SO suggests that SO is formed by sublimated S+. In this study, we also mapped HNC, C4H, c–C3H2, and HC3N with data from the PMO. We also find that HNC and NH3 are concentrated in L1524S and L1524N, respectively. Furthermore, we discuss the chemical differences between I04181SE and I04181W. The co-evolution between linear hydrocarbon and cyanopolyynes can be seen in I04181SE.

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THE PRECISE RADIO OBSERVATION OF THE 13C ISOTOPIC FRACTIONATION FOR CARBON CHAIN MOLECULE HC3N IN THE LOW-MASS STAR FORMING REGION L1527

Proceedings of the 71st International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2016.wh09 ◽

2016 ◽

Author(s):

Mitsunori Araki ◽

Koichi Tsukiyama ◽

Nobuhiko Kuze ◽

Takahiro Oyama ◽

Satoshi Yamamoto ◽

...

Keyword(s):

Isotopic Fractionation ◽

Radio Observation ◽

Carbon Chain ◽

Chain Molecule ◽

Mass Star ◽

Star Forming ◽

Low Mass

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The connection between the zig-zag structure of the hydrocarbon chain and the alternations in the properties of odd and even numbered chain compounds

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1929.0117 ◽

1929 ◽

Vol 124 (794) ◽

pp. 317-321 ◽

Cited By ~ 23

Keyword(s):

Physical Properties ◽

Single Crystal ◽

Hydrocarbon Chain ◽

Carbon Chain ◽

Chain Molecule ◽

X Rays ◽

X Ray ◽

Parallel Lines ◽

End Groups ◽

Chain Compounds

X-ray investigation of a single crystal on n -C 29 H 60 has shown that the CH 2 groups of the chain molecule lie equally spaced on two parallel rows, the lines between successive centres thus forming a zig-zag. Analysis of X-ray photographs of similar substances leaves no doubt that the same chain persists not only through a whole series of hydrocarbons, but is also present in a large number of other carbon chain compounds. The object of this paper is to show how a number of observations on their physical properties are connected with the zig-zag structure of the chain molecule. The following fig. 1 represents a section through a crystal. X-rays show that the chains lie side by side, the parallel lines in the drawing being the chain axes. The ends of the molecules, marked by small circles, arrange themselves in equidistant parallel layers. In the following deductions we consider molecules in which the two end groups are chemically identical, such as hydrocarbons, dibasic acids, etc.

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The Course of Autoöxidation Reactions in Polyisoprenes and Allied Compounds. Part. VI. The Peroxidation of Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3540161 ◽

1943 ◽

Vol 16 (4) ◽

pp. 790-804

Author(s):

Ernest Harold Farmer ◽

Alvapillai Sundralingam

Keyword(s):

Diatomic Molecule ◽

Oxidation Product ◽

Accurate Method ◽

Carbon Chain ◽

Considerable Proportion ◽

Chain Molecule ◽

Potential Range ◽

Peroxide Content ◽

Long Chain ◽

Heterogeneous Element

Abstract Peroxides have repeatedly been shown to appear during the slow oxidation (perishing) of rubber in air, and during both its milling in air and the passage of air or oxygen through its solutions: yet in none of the recorded experiments has the production of any very substantial proportion of peroxide been demonstrated. This arises largely because, under many conditions of autoöxidation, no very considerable proportion of peroxide is present in the oxidation product at any stage, but in part because no convenient and reasonably accurate method of determining the peroxide content in so insoluble a substance as rubber has been available. It must inevitably happen in a long-chain molecule of polymer-homologous type containing on the average about 5,000 autoxidisable olefinic units that the progressive entrance of a heterogeneous element will yield a large variety of closely similar products if attack is fairly evenly distributed over the chain, but when, as in the case of oxygen, the heterogeneous element enters the hydrocarbon as a diatomic molecule, the atoms in which can ultimately separate and become attached to the carbon chain in a variety of ways, and causes, as the result of its progressive incorporation, scission of the chain at an ever-increasing number of the olefinic units, then the potential range of diversity of the products becomes enormously increased.

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Functional Characterization of a Variant Factor XII (F XII Locarno) in a Cross Reacting Material Positive F XII Deficient Plasma

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648416 ◽

1992 ◽

Vol 67 (02) ◽

pp. 219-225 ◽

Cited By ~ 6

Author(s):

Walter A Wuillemin ◽

Miha Furlan ◽

Hans Stricker ◽

Bernhard Lämmle

Keyword(s):

Dextran Sulfate ◽

Functional Characterization ◽

Healthy Woman ◽

Chain Molecule ◽

Plasma Kallikrein ◽

Factor Xii ◽

Single Chain ◽

Sulfate Adsorption ◽

Prolonged Incubation ◽

Functional Studies

SummaryThe plasma of a healthy woman was found to contain half normal factor XII (FXII) antigen level (0.46 U/ml) without any FXII clotting activity (<0.01 U/ml). The variant FXII in this plasma, denoted as FXII Locarno, was partially characterized by immunological and functional studies on the proposita’s plasma. FXII Locarno is a single chain molecule with the same size (M r = 80 kDa) as normal FXII. Isoelectric focusing suggested an excess of negative charge in the variant FXII as compared to normal FXII. In contrast to FXII in normal plasma, FXII Locarno was not proteolytically cleaved upon prolonged incubation of proposita’s plasma with dextran sulfate. Adsorption to kaolin was similar for both, abnormal and normal FXII. Incubation of the proposita’s plasma with dextran sulfate and exogenous plasma kallikrein showed normal cleavage of FXII Locarno outside of the tentative disulfide loop Cys340-Cys467, but only partial cleavage within this disulfide loop. Furthermore, plasma kallikrein-cleaved abnormal FXII showed neither amidolytic activity nor proteolytic activity against factor XI and plasma prekallikrein.These results suggest a structural alteration of FXII Locarno, affecting the plasma kallikrein cleavage site Arg353-Val354 and thus formation of activated FXII (a-FXIIa).

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