Refractive index and density of ammonia ice at different temperatures of deposition

Satorre, M. Á.; Leliwa-Kopystyński, J.; Santonja, C.; Luna, R.

doi:10.1016/j.icarus.2013.04.023

Cited by 30 publications

(37 citation statements)

References 33 publications

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“…The deposition was monitored using helium-neon (He-Ne) laser interferometry to determine the thickness of the ice (Hudgins et al 1993;Westley et al 1998;Fulvio et al 2009). With a refractive index of the mixed ice of 1.3±0.1 determined via the method outlined by Baratta & Palumbo (1998), Romanescu et al (2010), and Satorre et al (2013), we calculate the thickness of the deposited ice to be 500±50 nm. The ratio of ammonia (NH 3 ) to carbon monoxide (CO) after the deposition was determined to be 4±1 to 1, as calculated via infrared spectroscopy using known column densities as derived from the integrated absorption coefficients of the infrared absorption features of ammonia and carbon monoxide: the CO υ 1 band at 2139 cm −1 with 1.1×10 −17 cm mol −1 (Gerakines et al 1995) and the NH 3 υ 2 band at 1092 cm −1 with 1.7×10 −17 cm mol…”

Section: Methodsmentioning

confidence: 99%

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

Förstel

Maksyutenko

Jones

et al. 2016

ApJ

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We report on the formation of organic amide polymers via carbonyl-amino group linkages in carbon monoxide and ammonia bearing energetically processed ices of astrophysical relevance. The first group comprises molecules with one carboxyl group and an increasing number of amine moieties starting with formamide (45 u), urea (60 u), and hydrazine carboxamide (75 u). The second group consists of species with two carboxyl (58 u) and up to three amine groups (73 u, 88 u, and 103 u). The formation and polymerization of these linkages from simple inorganic molecules via formamide und urea toward amide polymers is discussed in an astrophysical and astrobiological context. Our results show that long chain molecules, which are closely related to polypeptides, easily form by energetically processing simple, inorganic ices at very low temperatures and can be released into the gas phase by sublimation of the ices in star-forming regions. Our experimental results were obtained by employing reflectron time-of-flight mass spectroscopy, coupled with soft, single photon vacuum ultraviolet photoionization; they are complemented by theoretical calculations.

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Section: Methodsmentioning

confidence: 99%

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

Förstel

Maksyutenko

Jones

et al. 2016

ApJ

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“…(taken from Satorre et al 2013). The column densities were calculated using the integrated optical depth of the bands in the near-and mid-IR at 1070, 1625, 3373, 4480, and 4995 cm −1 .…”

Section: Nh 3 Icementioning

confidence: 99%

Interstellar ice analogs: band strengths of H₂O, CO₂, CH₃OH, and NH₃in the far-infrared region

Giuliano

Escribano

Martín-Doménech

et al. 2014

A&A

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Context. Whereas observational astronomy now routinely extends to the far-infrared region of the spectrum, systematic laboratory studies are sparse. In particular, experiments on laboratory analogs performed through the years have provided information mainly about the band positions and shapes, while information about the band strengths are scarce and derivable principally from the optical constants. Aims. We measure the band strengths in the far-infrared region of interstellar ice analogs of astrophysically relevant species, such as H 2 O, CO 2 , CH 3 OH, and NH 3 , deposited at low temperature (8-10 K), followed by warm-up, to induce amorphous-crystalline phase transitions when relevant. Methods. The spectra of pure H 2 O, NH 3 , and CH 3 OH ices have been measured in the near-, mid-and far-infrared spectroscopic regions using the Interstellar Astrochemistry Chamber (ISAC) ultra-high-vacuum setup. In addition, far-infrared spectra of NH 3 and CO 2 were measured using a different set-up equipped with a bolometer detector. Band strengths in the far-infrared region were estimated using the corresponding near-and mid-infrared values as a reference. We also performed theoretical calculations of the amorphous and crystalline structures of these molecules using solid state computational programs at density functional theory (DFT) level. Vibrational assignment and mode intensities for these ices were predicted. Results. Infrared band strengths in the 25-500 μm range have been determined for the considered ice samples by direct comparison in the near-and mid-infrared regions. Our values were compared to those we calculated from the literature complex index of refraction. We found differences of a factor of two between the two sets of values. Conclusions. The calculated far-infrared band strengths provide a benchmark for interpreting the observational data from future space telescope missions, allowing the estimation of the ice column densities.

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“…The film thickness was chosen to give a high band contrast with respect to the infrared absorptions, without saturating the bands. At such thicknesses, the ion beam passes through the film with an almost constant energy deposition of about 250 eV/Å (Zn projectile) and 130 eV/Å (Ne projectile), for a mean density of 0.73 g cm −3 for the NH 3 :CH 3 OH ice mixture (assuming a density of 0.67 g cm −3 for NH 3 ice (Satorre et al 2013) and the liquid value of 0.79 g/cm −3 for CH 3 OH). A Nicolet FTIR spectrometer (Magna 550) with a spectral resolution of 1 cm −1 was used.…”

Section: Heavy Ionsmentioning

confidence: 99%

Comparison of UV and high-energy ion irradiation of methanol:ammonia ice

Muñoz

Dartois

Boduch

et al. 2014

A&A

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Aims. The main goal of this work is to compare the effects induced in ices of astrophysical relevance by high-energy ions, simulating cosmic rays, and by vacuum ultraviolet (UV) photons. Methods. This comparison relies on in situ infrared spectroscopy of irradiated CH 3 OH:NH 3 ice. Swift heavy ions were provided by the GANIL accelerator. The source of UV was a microwave-stimulated hydrogen flow discharge lamp. The deposited energy doses were similar for ion beams and UV photons to allow a direct comparison. Results. A variety of organic species was detected during irradiation and later during ice warm-up. These products are common to ion and UV irradiation for doses up to a few tens of eV per molecule. Only the relative abundance of the CO product, after ice irradiation, was clearly higher in the ion irradiation experiments. Conclusions. For some ice mixture compositions, the irradiation products formed depend only weakly on the type of irradiation, swift heavy ions, or UV photons. This simplifies the chemical modeling of energetic ice processing in space.

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Refractive index and density of ammonia ice at different temperatures of deposition

Cited by 30 publications

References 33 publications

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

Interstellar ice analogs: band strengths of H₂O, CO₂, CH₃OH, and NH₃in the far-infrared region

Comparison of UV and high-energy ion irradiation of methanol:ammonia ice

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Refractive index and density of ammonia ice at different temperatures of deposition

Cited by 30 publications

References 33 publications

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

On the Formation of Amide Polymers via Carbonyl–amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

Interstellar ice analogs: band strengths of H2O, CO2, CH3OH, and NH3in the far-infrared region

Comparison of UV and high-energy ion irradiation of methanol:ammonia ice

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Interstellar ice analogs: band strengths of H₂O, CO₂, CH₃OH, and NH₃in the far-infrared region