Vibronic absorption spectra of condensed ring aromatic cation systems in solid argon

Andrews, Lester; Friedman, Ronald; Kelsall, Benuel J.

doi:10.1021/j100265a017

Cited by 33 publications

(31 citation statements)

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“…However, the weight of the corresponding determinant in the wavefunctions is almost constant for all polyacene radical cations with 0.87 from naphthalene to 0.82 for hexacene. Since the excitation energy of the B 3u transition decreases with increasing system size, it becomes the lowest excited state for tetracene at ADC(2) level, in agreement with the experimental data [75,77,78]. Since the B 3u transition is ungerade, it is one-photon allowed and thus exhibits substantial oscillator strength increasing from naphthalene with values of 0.084 and 0.058 at the theoretical levels of ADC(2)-s and ADC(2)-x, respectively, to 0.301 and 0.148 for pentacene, for example.…”

Section: Excited State Properties Of Polyacene Radical Cationssupporting

confidence: 87%

The low-lying excited states of neutral polyacenes and their radical cations: a quantum chemical study employing the algebraic diagrammatic construction scheme of second order

et al. 2010

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Section: Excited State Properties Of Polyacene Radical Cationssupporting

confidence: 87%

The low-lying excited states of neutral polyacenes and their radical cations: a quantum chemical study employing the algebraic diagrammatic construction scheme of second order

et al. 2010

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“…This assignment is based on previous studies relating to ACENE-3 spontaneous ionization and photoionization within M n ZSM-5 20,21 (M = Li þ , Na þ , K þ , etc.) as well as to investigations of ACENE-3 •þ in Ar and Ne matrices, 22,23 in silica materials, 24À26 and in solution. 27,28 The intensity of these bands increased considerably with time following…”

Section: ' Resultsmentioning

confidence: 99%

Influence of Gallium Isomorphous Substitution in the Acidic MFI Zeolite Framework on Hole Formation, Transfer, and Trapping upon Incorporation of Anthracene

et al. 2011

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The redox behavior of ACENE-3 upon sorption within the channels of Brønsted acidic H-GaZSM-5 is followed by using diffuse reflectance UVÀvisÀNIR spectrometry in parallel with continuous wave EPR techniques and with Raman spectrometry. Partial spontaneous ionization is clearly observed, whereas proton transfer does not occur. The intense internal proton electrostatic field, as well as the confinement effect on the occluded molecule, are put forward to explain charge separation and the long-lived ACENE-3 •þ radical cation. The compartmentalization of ACENE-3 •þ and trapped electron within H-GaZSM-5 hinders charge recombination but promotes hole transfer to the inner surface of the 10-membered ring (10-MR) channel. Pulsed X-band EPR experiments using the 2D-HYSCORE sequence were carried out to investigate the structural surrounding of unpaired electrons. The observation of electron couplings with 1 H, 29 Si, 69 Ga, and 71 Ga nuclei allows clear differentiation between the two successive charge separated states. The present results for H-GaZSM-5 are compared to previous analogous experiments conducted on H-AlZSM-5 for which hole transfer from the ACENE-3 organic molecule to the silicoaluminate framework was not observed at room temperature after the ACENE-3 spontaneous ionization in H-AlZSM-5. The hole transfer ΔG 0 is the key parameter in the nonadiabatic electron-transfer theory that explains the hole transfer at room temperature within H-GaZSM-5 and not within H-AlZSM-5.

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“…An estimate of the gas-phase origin bands for this radical cation can be made by comparing well-known laboratory gas-phase and Ar-matrix electronic spectra for other chemically similar PAH radical cations. For the cations of naphthalene (C 10 H 8 + ) ( Romanini et al, 1999;Salama and Allamandola, 1991 ), phenanthrene (C 14 H 10 + ) ( Andrews et al, 1985;Pino et al, 1999 ), acenaphthene (C 12 H 10 + ) ( Banisaukas et al, 2003;Biennier et al, 2003 ), anthracene (C 14 H 10 + ) ( Sukhorukov et al, 2004;, coronene (C 24 H 12 + ) ( Hardy et al, 2017; ) and pyrene (C 16 H 10 + ) ( Biennier et al, 2004;Salama and Allamandola, 1992 ), the shifts to lower wavenumber induced by the argon matrix are 95,98,223,266,232 and 352 cm −1 , respectively; the corresponding gas-phase line widths in jet-cold spectra are all quite broad, being 25, 16, 55, < 94, 106 and 145 cm −1 , respectively. Hence for cationic triphenylene, using these laboratory data and the Ar-matrix data in Table 1 , the gas-phase origins are predicted to fall in the 3970 -4010 Å and 6780 -6900 Å regions.…”

Section: Astrophysical Implicationsmentioning

confidence: 99%

Laboratory spectroscopy and astronomical significance of the fully-benzenoid PAH triphenylene and its cation

Kofman

Sarre

Hibbins

et al. 2017

Molecular Astrophysics

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a b s t r a c tTriphenylene (C 18 H 12 ) is a highly symmetric polycyclic aromatic hydrocarbon (PAH) molecule with a 'fully-benzenoid' electronic structure. This confers a high chemical stability compared with PAHs of similar size. Although numerous infrared and UV-vis experimental spectroscopic and theoretical studies of a wide range PAHs in an astrophysical context have been conducted, triphenylene and its radical cation have received almost no attention. There exists a huge body of spectroscopic evidence for neutral and ionised PAHs in astrophysical sources, obtained principally through detection of infrared emission features that are characteristic of PAHs as a chemical class. However, it has so far not proved possible to identify spectroscopically a single isolated PAH in space, although PAHs including triphenylene have been detected mass spectrometrically in meteorites. In this work we focus on recording laboratory electronic spectra of neutral and ionised triphenylene between 220 and 780 nm, trapped in H 2 O ice and solid argon at 12 K. The studies are motivated by the potential for spectroscopic astronomical detection of electronic absorption spectra of PAHs in ice mantles on interstellar grains as discussed by Linnartz (2014), and were performed also in a cold Ar matrix to provide guidance as to whether triphenylene (particularly in its singly positively ionised form) could be a viable candidate for any of the unidentified diffuse interstellar absorption bands. Based on the argon-matrix experimental results, comparison is made with previously unpublished astronomical spectra near 400 nm which contain broad interstellar absorption features consistent with the predictions from the laboratory matrix spectra, thus providing motivation for the recording of gas-phase electronic spectra of the internally cold triphenylene cation.

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Vibronic absorption spectra of condensed ring aromatic cation systems in solid argon

Cited by 33 publications

References 0 publications

The low-lying excited states of neutral polyacenes and their radical cations: a quantum chemical study employing the algebraic diagrammatic construction scheme of second order

The low-lying excited states of neutral polyacenes and their radical cations: a quantum chemical study employing the algebraic diagrammatic construction scheme of second order

Influence of Gallium Isomorphous Substitution in the Acidic MFI Zeolite Framework on Hole Formation, Transfer, and Trapping upon Incorporation of Anthracene

Laboratory spectroscopy and astronomical significance of the fully-benzenoid PAH triphenylene and its cation

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