Laboratory spectra of cold gas phase polycyclic aromatic hydrocarbon cations, and their possible relation to the diffuse interstellar bands

Bréchignac, Philippe; Pino, T.; Boudin, N.

doi:10.1016/s1386-1425(00)00441-8

Cited by 41 publications

(32 citation statements)

References 33 publications

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“…[12, 8,8,10] (ν 65 ,ν 20 ,ν 50 ,ν 23 ) (10,12,10,14) [10,10,8,12] (ν 10 ,ν 12 ,ν 64 ,ν 22 ) (4,6,10,20) [10, 8,8,12] (ν 19 ,ν 51 ,ν 13 ,ν 6 ) (8,10,8,14) [8,10,10,12] (ν 62 ,ν 11 ,ν 58 ,ν 7 ) (8,10,8,6) [10,8,12,10] Py + (ν 11 ,ν 26 ,ν 65 ,ν 8 ) (8,8,35,15) [14,8,12,10] (ν 33 ,ν 10 ,ν 52 ,ν 64 ) (6,4,16,12) [8,14,10,12] (ν 5 ,ν 32 ,ν 12 ,ν 59 ) (8,6,12,6) [12,12,14,10] (ν 7 ,ν 53 ,ν 44 (8,4,4,14) [12,10,8,10] (ν 9 ,ν 12 ,ν 60 ,ν 19 ) (10, 4,6,20) [10,12,8,10] (ν 6 ,ν 54 ,ν 48 ,ν 14 ) (10,4,6,18) [8,12,10,10] (ν 59 ,ν 10 ,ν 20 ,ν 8 ) (18,10,18,10)…”

Section: Normal Modesmentioning

confidence: 99%

“…[10,8,10,12] (ν 58 ,ν 15 ,ν 52 ,ν 13 ) (10, 6,4,6) [ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 40 of 40…”

Section: Normal Modesunclassified

“…In the recent past, detailed theoretical studies on the radical cation of naphthalene (Np + ), anthracene (An + ), tetracene (Tn + ), pentacene (Pn + ), hexacene (Hn + ) 20-24 and l-C 3 H 2 neutral 25 were carried out in our group. The theoretical results on the structure and dynamics of these radical cations were compared with those recorded in the laboratory 7,26,27 and also stellar meaamount of laboratory [6][7][8][9][10][11][12][13][14][15][16][17][18][19] and stellar 14 spectroscopy data on these radical cations is the primary motivation behind this study. Apart from this, it appears interesting to understand the complex vibronic coupling in the electronic excited states [20][21][22]24,25,31 of these species.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Study on Molecules of Interstellar Interest. II. Radical Cation of Compact Polycyclic Aromatic Hydrocarbons

Reddy

Mahapatra

2015

J. Phys. Chem. B

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Radical cations of polycyclic aromatic hydrocarbons have been postulated to be molecular carriers of diffuse spectroscopic features observed in the interstellar medium. Several important observations made by stellar and laboratory spectroscopists motivated us to undertake a detailed theoretical study attempting to validate the recorded data. In continuation of our work on this subject, we here focus on a detailed theoretical study of the doublet ground (X̃) and low-lying excited (Ã, B̃, and C̃) electronic states of the radical cation of phenanthrene, pyrene, and acenaphthene molecule. A multistate and multimode theoretical model in a diabatic electronic basis is developed here through extensive ab initio quantum chemistry calculations. Employing this model, first-principles nuclear dynamics calculations are carried out to unravel the spectral assignment, time-dependent dynamics, and photostability of the mentioned electronic states of the radical cations. The theoretical results compare well with the observed experimental data.

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Section: Normal Modesmentioning

confidence: 99%

Section: Normal Modesunclassified

Section: Introductionmentioning

confidence: 99%

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Theoretical Study on Molecules of Interstellar Interest. II. Radical Cation of Compact Polycyclic Aromatic Hydrocarbons

Reddy

Mahapatra

2015

J. Phys. Chem. B

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“…The lifetime of the excited electronic state for PAH-like molecules can be as short as 10 −12 s, against the 10 −8 s typical of an electronic transition involving the emission of radiation (Birks 1970). Indeed, according to recent results by Bréchignac et al (2001), the measured lorentzian broadening in electronic transitions of the naphtalene cation hints at excited state lifetimes even slightly shorter than 10 −12 s. The rotational fine structure of the band is progressively smoothed out for decreasing lifetimes, leaving just a barely detectable asymmetry in the most extreme case we considered here. The rotational profile of the modelled electronic absorption band expected for the different ionization equilibria considered are presented in Fig.…”

Section: Resultsmentioning

confidence: 96%

Testing the “strong” PAHs hypothesis

Malloci

Mulas

Benvenuti

2003

A&A

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Abstract. The so-called "strong" Polycyclic Aromatic Hydrocarbons (PAHs) hypothesis postulates that isolated PAHs, which are thought to be the carriers of the Unidentified Infrared Bands, ought to be also responsible for a large number of Diffuse Interstellar Bands (DIBs). In this framework, the spectral profile of such DIBs should be due to unresolved rotational structure of vibronic absorption bands, the rotation of the molecule being by and large governed by the interaction with the interstellar radiation field. In this paper we quantitatively test the above hypothesis against the observational constraint of DIBs profile invariance, by using Monte-Carlo methods to model the photophysics of a prototypical interstellar PAH, namely the ovalene cation (C 32 H + 14 ). Our results show that the predicted rotational band profiles are remarkably insensitive to both the ambient conditions and the assumed values of some poorly known parameters. The present model therefore offers a quantitative link between any given PAH and the observed DIB profiles, providing a valuable tool for molecular identification.

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“…in cold jets, became more feasible, more and more experimental measurements of PAH spectra became available (see e.g. Pino et al 1999;Bréchignac et al 2001;Biennier et al 2003;Biennier 2004;Tan et al 2005;Staicu et al 2006;Rouillé et al 2007;Salama et al 2008), but mainly in the visible and near-UV, to compare them with observations of the DIBs. PAH spectra in the vacuum UV, especially for cations, being much more difficult and less promising for a direct identification, were left behind.…”

Section: Pahs Enter the Scenementioning

confidence: 99%

Polycyclic Aromatic Hydrocarbons and the Extinction Curve

Mulas

Malloci

Joblin

et al. 2011

EAS Publications Series

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Abstract. Aromatic carbon, in some form, has been an essential ingredient by and large in all models of the extinction curve, since the original proposal to attribute the bump at 217.5 nm to "astronomical graphite". This aromatic carbon is most naturally identified, in up to date models, with a population of Polycyclic Aromatic Hydrocarbons (PAHs), free and/or clustered. In all models, this PAH population accounts for the far-UV nonlinear rise in the extinction curve, contributes to the bump and possibly part of the large set of unidentified, discrete absorption features in the visible (the Diffuse Interstellar Bands). We review the current state of our understanding of the contribution of PAHs to interstellar extinction, and what constraints can be imposed on the PAH population by fitting extinction models to observations.

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Laboratory spectra of cold gas phase polycyclic aromatic hydrocarbon cations, and their possible relation to the diffuse interstellar bands

Cited by 41 publications

References 33 publications

Theoretical Study on Molecules of Interstellar Interest. II. Radical Cation of Compact Polycyclic Aromatic Hydrocarbons

Theoretical Study on Molecules of Interstellar Interest. II. Radical Cation of Compact Polycyclic Aromatic Hydrocarbons

Testing the “strong” PAHs hypothesis

Polycyclic Aromatic Hydrocarbons and the Extinction Curve

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