Infrared spectra of solid hydrocarbons at very low temperatures

Comeford, J. J.; Gould, John

doi:10.1016/0022-2852(61)90110-2

Cited by 29 publications

(14 citation statements)

References 10 publications

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“…This process is associated with a rate constant k 1 of 1.3 ± 0.2 × 10 −5 s −1 . The competing hydrogen atom addition leading to the ethyl Comeford & Gould (1960). Kim et al (2010).…”

Section: Discussionmentioning

confidence: 99%

“…The weak absorptions of the ethyl radical were identified via its 532 cm −1 and 3110 cm −1 absorption bands (Bennett et al 2006;Pacansky & Schrader 1983). Ethane (C 2 H 6 ) and n-butane (C 4 H 10 ) are tricky to discriminate since their most intense features at 2935, 2879, 1462, and 1373 cm −1 can be assigned to either molecule (Comeford & Gould 1960;Kim et al 2010). However, the newly emerging absorptions at 2957 cm −1 and 2858 cm −1 can be attributed to n-butane.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

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On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

Zhou

Maity

Abplanalp

et al. 2014

ApJ

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The chemical processing of ethylene ices (C 2 H 4 ) by energetic electrons was investigated at 11 K to simulate the energy transfer processes and synthesis of new molecules induced by secondary electrons generated in the track of galactic cosmic ray particles. A combination of Fourier transform infrared spectrometry (solid state) and quadrupole mass spectrometry (gas phase) resulted in the identification of six hydrocarbon molecules: methane (CH 4 ), the C2 species acetylene (C 2 H 2 ), ethane (C 2 H 6 ), the ethyl radical (C 2 H 5 ), and-for the very first time in ethylene irradiation experiments-the C4 hydrocarbons 1-butene (C 4 H 8 ) and n-butane (C 4 H 10 ). By tracing the temporal evolution of the newly formed molecules spectroscopically online and in situ, we were also able to fit the kinetic profiles with a system of coupled differential equations, eventually providing mechanistic information, reaction pathways, and rate constants on the radiolysis of ethylene ices and the inherent formation of smaller (C1) and more complex (C2, C4) hydrocarbons involving carbon-hydrogen bond ruptures, atomic hydrogen addition processes, and radical-radical recombination pathways. We also discuss the implications of these results on the hydrocarbon chemistry on Titan's surface and on ice-coated, methane-bearing interstellar grains as present in cold molecular clouds such as TMC-1.

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“…This process is associated with a rate constant k 1 of 1.3 ± 0.2 × 10 −5 s −1 . The competing hydrogen atom addition leading to the ethyl Comeford & Gould (1960). Kim et al (2010).…”

Section: Discussionmentioning

confidence: 99%

Section: Infrared Spectroscopymentioning

confidence: 99%

On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

Zhou

Maity

Abplanalp

et al. 2014

ApJ

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“…The gas phase was monitored by a quadrupole mass spectrometer (Balzer QMG 420) operating in a residual gas analyzer mode with an electron impact ionization energy of 100 eV and a mass range of up to 200 amu. Figure 1 depicts a mid-infrared spectrum of the ethane ices as deposited at 10 K. The vibrational assignments are compared with literature values in Table 1 (Comeford & Gould 1960;Hepp & Herman 1999). Our experimental conditions lead to the preparation of amorphous ethane at 10 K; this is evident from the lacking fine structures of the ν 6 , ν 11 , and ν 12 bands in the range of 1600-700 cm −1 ; in particular, the fine structures of the CH 3 deformation modes are missing (Tejada & Eggers 1976;Wisnosky et al 1983a).…”

Section: Methodsmentioning

confidence: 99%

“…Three additional bands are identified for n-butane at 966 (ν 35 ), 2860, and 2957 cm −1 (ν 12 , ν 27 ). A set of bands appearing only at 100 nA are assigned to butene (Barnes & Howells 1973;Comeford & Gould 1960). Upon heating, the ethane matrix sublimed in the range of 60-70 K, together with the volatile products methane, acetylene, and ethylene.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

Laboratory Studies on the Irradiation of Solid Ethane Analog Ices and Implications to Titan's Chemistry

Kim

Bennett

Chen

et al. 2010

ApJ

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Pure ethane ices (C 2 H 6 ) were irradiated at 10, 30, and 50 K under contamination-free, ultrahigh vacuum conditions with energetic electrons generated in the track of galactic cosmic-ray (GCR) particles to simulate the interaction of GCRs with ethane ices in the outer solar system. The chemical processing of the samples was monitored by a Fourier transform infrared spectrometer and a quadrupole mass spectrometer during the irradiation phase and subsequent warm-up phases on line and in situ in order to extract qualitative (products) and quantitative (rate constants and yields) information on the newly synthesized molecules. Six hydrocarbons, methane (CH 4 ), acetylene (C 2 H 2 ), ethylene (C 2 H 4 ), and the ethyl radical (C 2 H 5 ), together with n-butane (C 4 H 10 ) and butene (C 4 H 8 ), were found to form at the radiation dose reaching 1.4 eV per molecule. The column densities of these species were quantified in the irradiated ices at each temperature, permitting us to elucidate the temperature and phase-dependent production rates of individual molecules. A kinetic reaction scheme was developed to fit column densities of those species produced during irradiation of amorphous/crystalline ethane held at 10, 30, or 50 K. In general, the yield of the newly formed molecules dropped consistently for all species as the temperature was raised from 10 K to 50 K. Second, the yield in the amorphous samples was found to be systematically higher than in the crystalline samples at constant temperature. A closer look at the branching ratios indicates that ethane decomposes predominantly to ethylene and molecular hydrogen, which may compete with the formation of n-butane inside the ethane matrix. Among the higher molecular products, n-butane dominates. Of particular relevance to the atmosphere of Saturn's moon Titan is the radiation-induced methane production from ethane-an alternative source of replenishing methane into the atmosphere. Finally, we discuss to what extent the n-butane could be the source of "higher organics" on Titan's surface thus resembling a crucial sink of condensed ethane molecules.

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“…38 The remaining absorption features positioned from 2960-2870 cm À1 and at 1458 cm À1 can be confidently assigned to C-H stretching and -CH 2 deformation vibrations of hydrocarbons. 40 As the substrate is heated to 150 K, these features remain as relatively intense peaks in the mid-IR spectrum (Fig. 4b), indicating that higherorder aliphatic species are produced by ethylene irradiation over the irradiated methane and ethane condensates investigated earlier.…”

Section: Infrared Spectroscopymentioning

confidence: 76%

On the chemical processing of hydrocarbon surfaces by fast oxygen ions

Ennis

Yuan

Sibener

et al. 2011

Phys. Chem. Chem. Phys.

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Solid methane (CH(4)), ethane (C(2)H(6)), and ethylene (C(2)H(4)) ices (thickness: 120 ± 40 nm; 10 K), as well as high-density polyethylene (HDPE: [C(2)H(4)](n)) films (thickness: 130 ± 20 nm; 10, 100, and 300 K), were irradiated with mono-energetic oxygen ions (Φ ~ 6 × 10(15) cm(-2)) of a kinetic energy of 5 keV to simulate the exposure of Solar System hydrocarbon ices and aerospace polymers to oxygen ions sourced from the solar wind and planetary magnetospheres. On-line Fourier-transform infrared spectroscopy (FTIR) was used to identify the following O(+) induced reaction pathways in the solid-state: (i) ethane formation from methane ice via recombination of methyl (CH(3)) radicals, (ii) ethane conversion back to methane via methylene (CH(2)) retro-insertion, (iii) ethane decomposing to acetylene via ethylene through successive hydrogen elimination steps, and (iv) ethylene conversion to acetylene via hydrogen elimination. No changes were observed in the irradiated PE samples via infrared spectroscopy. In addition, mass spectrometry detected small abundances of methanol (CH(3)OH) sublimed from the irradiated methane and ethane condensates during controlled heating. The detection of methanol suggests an implantation and neutralization of the oxygen ions within the surface where atomic oxygen (O) then undergoes insertion into a C-H bond of methane. Atomic hydrogen (H) recombination in forming molecular hydrogen and recombination of implanted oxygen atoms to molecular oxygen (O(2)) are also inferred to proceed at high cross-sections. A comparison of the reaction rates and product yields to those obtained from experiments involving 5 keV electrons, suggests that the chemical alteration of the hydrocarbon ice samples is driven primarily by electronic stopping interactions and to a lesser extent by nuclear interactions.

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Infrared spectra of solid hydrocarbons at very low temperatures

Cited by 29 publications

References 10 publications

On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

Laboratory Studies on the Irradiation of Solid Ethane Analog Ices and Implications to Titan's Chemistry

On the chemical processing of hydrocarbon surfaces by fast oxygen ions

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