Spectroscopy of Dibenzorubicene: Experimental Data for a Search in Interstellar Spectra

Rouillé, Gaël; Steglich, Mathias; Jäger, Cornelia; Huisken, F.; Henning, Thomas; Theumer, Gabriele; Бауер, И.; Knölker, Hans‐Joachim

doi:10.1002/cphc.201100135

Cited by 7 publications

(7 citation statements)

References 27 publications

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“…Nevertheless, DBR can be excluded as possible DIB carrier. While the case of the neutral molecule is discussed in another article (Rouillé et al 2011), cationic DBR does not exhibit sufficiently narrow bands -at least for wavelengths shorter than 900 nm. The first electronic transition of HBC in the gas phase causes some narrow and very weak bands between 410 and 435 nm (24390 -22990 cm −1 ) not able to reproduce any DIB (Kokkin et al 2008).…”

Section: Implications For the Carriers Of The Diffusementioning

confidence: 98%

“…The measured spectra of neutral and ionized matrixisolated DBR are displayed in the top panel of Figure 4. Detailed information on the spectroscopy, both in absorption and emission, of neutral DBR is given in another paper (Rouillé et al 2011). DBR can be regarded as a planar fragment of the fullerene C 70 (with H-saturated dangling bonds), which was recently discovered in the planetary nebula Tc 1 (Cami et al 2010).…”

Section: Dibenzorubicene (C 30 H 14 )mentioning

confidence: 99%

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Can Neutral and Ionized Polycyclic Aromatic Hydrocarbons Be Carriers of the Ultraviolet Extinction Bump and the Diffuse Interstellar Bands?

Steglich

Bouwman

Huisken

et al. 2011

ApJ

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Up to now, no laboratory-based study has investigated polycyclic aromatic hydrocarbon (PAH) species as potential carriers of both the diffuse interstellar bands (DIBs) and the 2175Å UV bump. We examined the proposed correlation between these two features by applying experimental and theoretical techniques on two specific medium-sized/large PAHs (dibenzorubicene C 30 H 14 and hexabenzocoronene C 42 H 18 ) in their neutral and cationic states. It was already shown that mixtures of sufficiently large, neutral PAHs can partly or even completely account for the UV bump. We investigated how the absorption bands are altered upon ionization of these molecules by interstellar UV photons. The experimental studies presented here were realized by performing matrix isolation spectroscopy with subsequent far-UV irradiation. The main effects were found to be a broadening of the absorption bands in the UV combined with slight redshifts. The position of the complete ππ * absorption structure around 217.5 nm, however, remains more or less unchanged which could explain the observed position invariance of the interstellar bump for different lines of sight. This favors the assignment of this feature to the interstellar PAH population. As far as the DIBs are concerned, neither our investigations nor the laboratory studies carried out by other research groups support a possible connection with this class of molecules. Instead, there are reasonable arguments that neutral and singly ionized cationic PAHs cannot be made responsible for the DIBs.

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Section: Implications For the Carriers Of The Diffusementioning

confidence: 98%

Section: Dibenzorubicene (C 30 H 14 )mentioning

confidence: 99%

Can Neutral and Ionized Polycyclic Aromatic Hydrocarbons Be Carriers of the Ultraviolet Extinction Bump and the Diffuse Interstellar Bands?

Steglich

Bouwman

Huisken

et al. 2011

ApJ

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“…The matrix isolation spectroscopy (MIS) setup was described in previous studies (Steglich et al 2010;Rouillé et al 2011). Briefly, it consists of a commercial spectrophotometer (JASCO V-670 EX) coupled to a vacuum chamber by means of optical fibers.…”

Section: Matrix Isolation Spectroscopymentioning

confidence: 99%

On the Relevance of Polyynyl-Substituted Polycyclic Aromatic Hydrocarbons to Astrophysics

Rouillé

Steglich

Carpentier

et al. 2012

ApJ

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We report on the absorption spectra of the polycyclic aromatic hydrocarbon (PAH) molecules anthracene, phenanthrene, and pyrene carrying either an ethynyl (−C 2 H) or a butadiynyl (−C 4 H) group. Measurements were carried out in the mid infrared at room temperature on grains embedded in CsI pellets and in the near ultraviolet at cryogenic temperature on molecules isolated in Ne matrices. The infrared measurements show that interstellar populations of polyynyl-substituted PAHs would give rise to collective features in the same way non-substituted PAHs give rise to the aromatic infrared bands. The main features characteristic of the substituted molecules correspond to the acetylenic CH stretching mode near 3.05 µm and to the almost isoenergetic acetylenic CCH in-and out-of-plane bending modes near 15.9 µm. Sub-populations defined by the length of the polyynyl side group cause collective features which correspond to the various acetylenic CC stretching modes. The ultraviolet spectra reveal that the addition of an ethynyl group to a non-substituted PAH molecule results in all its electronic transitions being redshifted. Due to fast internal energy conversion, the bands at shorter wavelengths are significantly broadened. Those at longer wavelengths are only barely affected in this respect. As a consequence, their relative peak absorption increases. The substitution with the longer butadiynyl chain causes the same effects with a larger magnitude, resulting in the spectra to show a prominent if not dominating π-π * transition at long wavelength. After discussing the relevance of polyynyl-substituted PAHs to astrophysics, we conclude that this class of highly conjugated, unsaturated molecules are valid candidates for the carriers of the diffuse interstellar bands.

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“…Since both, C 60 and C 70 fullerenes, have been identified in a planetary nebula, we assumed that 1 may also be present in interstellar space. Therefore, we performed extensive spectroscopic studies of 1 and compared the data with those of interstellar spectra . Even though we did not find coincidences between the spectral properties of 1 and several interstellar phenomena, the presence in space cannot be completely ruled out.…”

Section: Introductionmentioning

confidence: 89%

“…%)=347 (100, [ M ] + ), 372 (39), 370 (18), 368 (6), 221 (8), 204 (17), 186 (32), 59 (10); HRMS (EI): m / z calcd for C 30 H 14 : 374.1096; found: 374.1084. Detailed IR and UV/Vis spectroscopic studies of 1 have been published by us previously . Crystallization afforded two different modifications of 1 which were analyzed by X‐ray diffractometry.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Crystal Structure of Dimorphic Dibenzo[cde,opq]rubicene

Suresh

Whitener

Theumer

et al. 2019

Chemistry A European J

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Spectroscopy of Dibenzorubicene: Experimental Data for a Search in Interstellar Spectra

Cited by 7 publications

References 27 publications

Can Neutral and Ionized Polycyclic Aromatic Hydrocarbons Be Carriers of the Ultraviolet Extinction Bump and the Diffuse Interstellar Bands?

Can Neutral and Ionized Polycyclic Aromatic Hydrocarbons Be Carriers of the Ultraviolet Extinction Bump and the Diffuse Interstellar Bands?

On the Relevance of Polyynyl-Substituted Polycyclic Aromatic Hydrocarbons to Astrophysics

Synthesis and Crystal Structure of Dimorphic Dibenzo[cde,opq]rubicene

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