Integrated Near‐Infrared Band Strengths of Solid CH<sub>4</sub>and Its Mixtures with N<sub>2</sub>

Brunetto, R.; Caniglia, G.; Baratta, G. A.; Palumbo, M. E.

doi:10.1086/591509

Cited by 63 publications

(58 citation statements)

References 19 publications

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“…It can be verified that the current normalized A-values are in fair agreement with the work of Brunetto et al (2008), Mulas et al (1998) (band 3009 cm −1 ), and Gerakines et al (2005) (band 1300 cm −1 ). For the carbon budget calculation, we assume that the band at 4202 cm −1 (ν 1 + ν 4 ) is the adequate one, as described in Sect.…”

Section: Ch 4 Analysissupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

“…For the ν 1 + ν 4 band, we used A = 3.59 × 10 −19 cm molecule −1 (Brunetto et al 2008). The CH 4 ice layer thickness of (1.78 ± 0.10) μm has been determined by considering molar mass 16.042 g/mol and the density 0.403 g/cm 3 (Brunetto et al 2008). Figure 1b shows a close look at the profiles of ν 3 and ν 4 fundamental bands of the CH 4 pure ice film prior to irradiation, which are consistent with that of the crystalline phase II structure with some amorphous features (Chapados & Cabana 1972;Pearl et al 1991).…”

Section: Methodsmentioning

confidence: 99%

“…To find coherent A-values, the column densities of all the others CH 4 transitions were normalized to the band 4202 cm −1 over a high fluence region (F = 1.0 × 10 13 ions/cm 2 ), assuming that the A-value reported by (Brunetto et al 2008) is the correct one. The normalized A-values obtained are displayed in the last column of Table 2.…”

Section: Ch 4 Analysismentioning

confidence: 99%

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Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Barros

Bordalo

Duarte

et al. 2011

A&A

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Laboratory data of CH 4 ice radiolysis promoted by fast heavy ions are obtained by infrared spectroscopy (FTIR). CH 4 molecules are condensed on a CsI substrate at 15 K, and the ice layer is bombarded by 220 MeV 16 O 7+ ion beam. The ice thickness is thin enough to be traversed by projectiles at constant velocity close to the equilibrium charge state. The induced CH 4 dissociation gives rise to the formation of molecular species CH 3 , C 2 H 2 , C 2 H 4 , C 2 H 6 , and C 3 H 8 . Their formation and dissociation cross sections are determined. C 2 H 6 represent the most abundant daughter molecules. The carbon budget analysis of CH 4 and its radiolysis products shows that the column density of carbon atoms contained in the methane destroyed during ion irradiation is 30−50% greater than the sum for the column densities of the newly formed species. As an astrophysical implication, the current results allow estimation of chemical reaction rates in ices covering interstellar grains.

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Section: Ch 4 Analysissupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Ch 4 Analysismentioning

confidence: 99%

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Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Barros

Bordalo

Duarte

et al. 2011

A&A

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“…3, the signal-to-noise ratio reached in our experiments in the considered spectral region is not enough to be able to tell if any band is present, so further experimental work is required. From the CH 4 bands at 2818, 4204, and 4302 cm −1 , using the band strength values given by Brunetto et al (2008), we estimated that the column density of CH 4 in the binary mixture CH 4 :H 2 O = 100:1 is about 7, 20, and 32 times higher than the CH 4 column density in the ternary mixture N 2 :CH 4 :H 2 O = 100:200:100, 100:30:10, and 100:10:3, respectively. Then we do not expect to detect the 7130 cm −1 CH 4 band in the spectra of the ternary mixtures.…”

Section: Binary and Ternary Mixturesmentioning

confidence: 99%

Near-infrared laboratory spectra of H₂O trapped in N₂, CH₄, and CO: hints for trans-Neptunian objects' observations

Fulvio¹,

Guglielmino²,

Favone³

et al. 2010

A&A

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Context. Recent mid-infrared spectroscopic observations of Pluto and Triton suggest a wide distribution of H 2 O ice into surface regions containing more volatile species such as N 2 , CH 4 , and CO. This disagrees with the common idea that because of their typical surface temperature, water should not be involved in volatile transport processes, standing easily segregated from the more volatile species. Aims. We analyse infrared H 2 O band profiles when water is diluted in solid matrices dominated by methane, carbon monoxide, and/or molecular nitrogen. We also show the results of temperature-related diffusion processes of solid N 2 into H 2 O ice deposited at different temperatures. Finally, we analyse ion irradiation effects for some of the mixtures considered. Methods. Solid samples were analysed by infrared (1.0-16.0 µm) transmission and reflectance spectroscopy at different temperatures (15-150 K), before and after ion irradiation with 200 keV protons. Results. When water is highly diluted in solid matrices, the profile of its near-infrared bands is strongly modified. Two narrow bands appear around 1.89 µm and 1.39 µm instead of the well known pure water ice bands at 2 µm and 1.5 µm, respectively. Furthermore, the peak position and width of the 1.89 and 1.39 µm bands depend on the initial mixture water is embedded in. The intensity of these bands decreases after ion irradiation. Conclusions. Since the mixtures considered closely resemble the surface composition of trans-Neptunian objects, experiments here discussed show that the bands around 1.89 µm and 1.39 µm are appropriate to investigating the presence of diluted water regions on their surface. In fact, the irradiation dose required for a significant decrease in their intensity would be accumulated on a timescale larger than the timescale for resurfacing processes on the surfaces of trans-Neptunian objects. Results shown here will contribute in a strong way to the interpretation of New Horizons near-infrared observations.

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Linking the IR transmittance to size and type of volcanic ash particles

et al. 2013

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[1] In this work, we applied infrared spectroscopy to investigate the spectral signature of the volcanic ash particles emitted during the 21-24 July 2001 eruption at Mount Etna, in Italy. We used a Bruker Equinox-55 Fourier transform infrared spectrometer in the range 7000-600 cm À1 (1.43-16.67 μm) and, for every collected spectrum, an image of the volcanic ash particles was recorded in the visible spectral range through the same microscope. These images were then analyzed by standard image analysis software in order to evaluate the main features of the particle: the length of the major and minor axes (Max and Min L), Feret diameter (FD), equivalent diameter (ED), and aspect ratio (AR). We measured transmission spectra in different conditions; spectra of one single particle (Single-Particle Measurement, SPM), spectra of a number of particles from two to ten (Multi-Particle Measurements type 1, MPM1) and of more than a hundred particles (Multi-Particle Measurements type 2, MPM2). For SPM, Max and Min L range between 5 and 24 μm and 3.5 and 15 μm, FD ranges between 5.5 and 25 μm, ED varies between 5 and 19 μm, and AR between 0.45 and 0.95. For MPM1 and MPM2, the mean values of Max and Min L are between 4-17 μm and 3-10 μm, FD and ED between 5 and 19 μm and 3.5 and 23 μm, and AR between 0.3 and 1. The optical depth spectra as a function of the wave number clearly show the presence of the Christiansen effect that produces high transmission at a given frequency in the infrared region (Christiansen frequency). We find that the effect depends on the particle size through a linear relation. Both the Christiansen effect and their relationship with the ash particle effective radius were compared with radiative transfer model simulations using different ash refractive indexes. The combined use of the linear relationship and the spectral position of the Christiansen frequency also indicated the possibility to characterize ash type. All these information can be used to improve the IR remote sensing volcanic ash quantitative estimations.Citation: Scollo, S., G. A. Baratta, M. E. Palumbo, S. Corradini, G. Leto, and G. Strazzulla (2013), Linking the IR transmittance to size and type of volcanic ash particles,

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Integrated Near‐Infrared Band Strengths of Solid CH₄and Its Mixtures with N₂

Cited by 63 publications

References 19 publications

Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Near-infrared laboratory spectra of H₂O trapped in N₂, CH₄, and CO: hints for trans-Neptunian objects' observations

Linking the IR transmittance to size and type of volcanic ash particles

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Integrated Near‐Infrared Band Strengths of Solid CH4and Its Mixtures with N2

Cited by 63 publications

References 19 publications

Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane

Near-infrared laboratory spectra of H2O trapped in N2, CH4, and CO: hints for trans-Neptunian objects' observations

Linking the IR transmittance to size and type of volcanic ash particles

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Integrated Near‐Infrared Band Strengths of Solid CH₄and Its Mixtures with N₂

Near-infrared laboratory spectra of H₂O trapped in N₂, CH₄, and CO: hints for trans-Neptunian objects' observations