Infrared spectroscopy and vibrational relaxation of CHx and CDx stretches on synthetic diamond nanocrystal surfaces

Chang, Huan‐Cheng; Lin, J.‐C.; Wu, Jianping; Chen, Kuei‐Hsien

doi:10.1021/j100028a007

Cited by 66 publications

(59 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The unambiguous detection of specific CH methine and methylene stretching modes, observed at 3.53 and 3.43 μm, associated with hydrogen atoms chemically bounded to diamond structure was demonstrated by Guillois et al (1999), by comparing emission spectra of astronomical sources to laboratory spectra of nanocrystal diamond films exposed to hydrogen by Chang et al (1995). These sources are different from the ones previously discussed for the 21 "microns" feature.…”

Section: (Nano-)diamondsmentioning

confidence: 95%

Observations of Interstellar Carbon Compounds

Dartois

2011

EAS Publications Series

View full text Add to dashboard Cite

Abstract. Infrared absorption and emission features observed spectroscopically in our Galaxy allow to probe the composition of solid dust grains, their evolution and thus follow the cycling of matter in the Galaxy. Many observables do reveal the presence of large amounts of carbonaceous particles in space, other than the PAH-like emission lines. The carbonaceous materials observed include amorphous carbons, diamondoids showing in emission for a few specific sources, and the recently detected fullerenes. An important hydrogenated amorphous carbon component (HAC or a-C:H), traced by the 2940 cm −1 structured absorption feature is observed against Galactic background sources. Since the discovery of this feature in the early eighties (Allen 1981), the observation of a-C:H has been extended to the mid-infrared by space observatories, giving insight into additional associated features. They are also observed in external galaxies, showing the ubiquitous nature of these components. We will focus on astronomical observations of organic matter other than PAHs, amorphous carbons and associated laboratory dust analogues relevant to astrophysical applications.

show abstract

Section: (Nano-)diamondsmentioning

confidence: 95%

Observations of Interstellar Carbon Compounds

Dartois

2011

EAS Publications Series

View full text Add to dashboard Cite

show abstract

“…These C-H bonds are active in the 3 µm region. Hydrogen atoms attached to different facets of the diamond surface give rise to different emission bands (Chang et al 1995;Lin et al 1996;Cheng et al 1997b). The peak frequency of these bands is determined by the crystallographic orientation of the surface plane, indicated by the Miller indices (e.g., (111)) and by the surface reconstruction (e.g.…”

Section: Diamondmentioning

confidence: 99%

Nanodiamonds around HD 97048 and Elias 1

Kerckhoven

Tielens²,

Waelkens

2002

A&A

102

104

View full text Add to dashboard Cite

Abstract.We present an analysis of ISO-SWS observations of the Herbig Ae/Be stars HD 97048 and Elias 1. Besides the well-known family of IR emission bands at 3.3, 6.2, "7.7", 8.6 and 11.2 µm these objects show strong, peculiar emission features at 3.43 and 3.53 µm. The latter two features show pronounced substructure which is very similar in the two sources. Comparison of the spectra of HD 97048 and Elias 1 with laboratory spectra of H-terminated diamond surfaces show excellent and very convincing agreement in peak position and spectral detail (Guillois et al. 1999). The position of the 3.53 µm band indicates a temperature of ∼1000 K. An analysis of the radiative energy budget makes us conclude that the diamond carrier of the 3.53 µm feature has typical sizes of 1-10 nm for HD 97048. A fit of the 3.53 µm feature with a theoretical, calculated profile indicates that the emitting diamonds in HD 97048 see a FUV flux of 5.The derived diamond mass, 1.5 × 10 −10 M , is only a tiny fraction of the total circumstellar dust mass and corresponds to only about 1 parts per billion relative to hydrogen. We discuss the origin of the diamond around these Herbig Ae/Be stars and conclude that most likely they are formed in situ. The implications for the nanodiamonds discovered in meteorites are also discussed.

show abstract

“…The hydrogenated solids comprise nanodiamonds, observed through vibration bands at 3.43 and 3.53 μm of hydrogen-terminated nanodiamonds (Chang et al 1995;Guillois et al 1999;Pirali et al 2007) in equilibrium with the stellar radiation field. They are observed close to the stars around very few objects (Habart et al 2004;Acke et al 2006;Goto et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Vacuum ultraviolet photolysis of hydrogenated amorphous carbons

Alata

Cruz-Díaz

Muñoz

et al. 2014

A&A

119

View full text Add to dashboard Cite

Context. The interstellar hydrogenated amorphous carbons (HAC or a-C:H) observed in the diffuse medium are expected to disappear in a few million years, according to the destruction time scale from laboratory measurements. The existence of a-C:H results from the equilibrium between photodesorption, radiolysis, hydrogenation and resilience of the carbonaceous network. During this processing, many species are therefore injected into the gas phase, in particular H 2 , but also small organic molecules, radicals or fragments. Aims. We perform experiments on interstellar a-C:H analogs to quantify the release of these species in the interstellar medium. Methods. The vacuum ultraviolet (VUV) photolysis of interstellar hydrogenated amorphous carbon analogs was performed at low (10 K) to ambient temperature, coupled to mass-spectrometry detection and temperature-programed desorption. Using deuterium isotopic substitution, the species produced were unambiguously separated from background contributions. Results. The VUV photolysis of hydrogenated amorphous carbons leads to the efficient production of H 2 molecules, but also to small hydrocarbons. Conclusions. These species are formed predominantly in the bulk of the a-C:H analog carbonaceous network, in addition to the surface formation. Compared with species made by the recombination of H atoms and physisorbed on surfaces, they diffuse out at higher temperatures. In addition to the efficient production rate, it provides a significant formation route in environments where the short residence time scale for H atoms inhibits H 2 formation on the surface, such as PDRs. The photolytic bulk production of H 2 with carbonaceous hydrogenated amorphous carbon dust grains can provide a very large portion of the contribution to the H 2 molecule formation. These dust grains also release small hydrocarbons (such as CH 4 ) into the diffuse interstellar medium, which contribute to the formation of small carbonaceous radicals after being dissociated by the UV photons in the considered environment. This extends the interstellar media environments where H 2 and small hydrocarbons can be produced.

show abstract

Infrared spectroscopy and vibrational relaxation of CHx and CDx stretches on synthetic diamond nanocrystal surfaces

Cited by 66 publications

References 10 publications

Observations of Interstellar Carbon Compounds

Observations of Interstellar Carbon Compounds

Nanodiamonds around HD 97048 and Elias 1

Vacuum ultraviolet photolysis of hydrogenated amorphous carbons

Contact Info

Product

Resources

About