Optical spectrum of proflavine and its ions

Bonaca, Ana; Bilalbegović, Goranka

doi:10.1016/j.cplett.2010.05.003

Cited by 8 publications

(15 citation statements)

References 46 publications

(92 reference statements)

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“…It is also noted that at a nominal ortho to para ratio of 3:1, the calculated spectrum of CH 2 CN − does not match the observed spectra. Similarly, a recent claim that proflavine and its anion, cation, and di-cation are responsible for the 4066 Å, 4363 Å, 4175 Å, and 5259 Å DIBs (Bonaca & Bilalbegović 2010) requires verification. The proposition is based on computed optical absorption wavelengths using pseudo-potential density functional theory methods.…”

Section: The Long and Eventful History Of Dib Candidatesmentioning

confidence: 99%

Abundances of PAHs in the ISM: confronting observations with experimental results

Gredel

Carpentier

Rouillé

et al. 2011

A&A

104

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Context. The identification of the carriers of the diffuse interstellar bands (DIBs) is the longest standing problem in the study of the interstellar medium. Here we present recent UV laboratory spectra of various polycyclic aromatic hydrocarbons (PAHs) and explore the potential of these molecules as carriers of the DIBs. Whereas, in the near IR range, the PAHs exhibit vibrational bands that are not molecule-specific, their electronic transitions occurring in the UV/vis provide characteristic fingerprints. The comparison of laboratory spectra calibrated in intensity with high signal-to-noise observational data in the UV enables us to establish new constraints on PAH abundances. Aims. From a detailed comparison of the gas-phase and Ne-matrix absorption spectra of anthracene, phenanthrene, pyrene, 2,3-benzofluorene, benzo[ghi]perylene, and hexabenzocoronene with new interstellar spectra, we aim to infer the abundance of these PAHs in the interstellar medium. Methods. We present spectra of PAHs measured at low temperature in the gas phase and in an Ne matrix, and present methods to derive absolute absorption cross sections for the matrix and gas phase spectra. We have obtained high signal to noise (S/N > 100) absorption spectra toward five lines of sight with reddenings of E B−V = 1−1.6 mag. The spectra cover the 3050−3850 Å wavelength region where the PAHs studied here show prominent absorption features. Results. From the observations, we infer upper limits in the fractional abundances of the PAHs studied here. Upper limits in the column densities of anthracene of 0.8−2.8 × 10 12 cm −2 and of pyrene and 2,3-benzofluorene ranging from 2−8 × 10 12 cm −2 are inferred. Upper limits in the column densities of benzo [ghi]perylene are 0.9−2.4 × 10 13 and 10 14 cm −2 for phenanthrene. The measurements indicate fractional abundances of anthracene, pyrene, and 2,3-benzofluorene of a few times 10 −10 . Upper limits in the fractional abundance of benzo [ghi]perylene of a few times 10 −9 and of phenanthrene of few times 10 −8 are inferred. Toward CPD −32 • 1734, we found near 3584 Å an absorption line of OH + , which was discovered in the interstellar medium only very recently. Conclusions. The fractional abundances of PAHs inferred here are up to two orders of magnitude lower than estimated total PAH abundances in the interstellar medium. This indicates that either neutral PAHs are not abundant in translucent molecular clouds or that a PAH population with a wide variety of molecules is present.

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Section: The Long and Eventful History Of Dib Candidatesmentioning

confidence: 99%

Abundances of PAHs in the ISM: confronting observations with experimental results

Gredel

Carpentier

Rouillé

et al. 2011

A&A

104

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“…The near‐UV channel of COS shows a high sensitivity in the region between 200 and 300 nm where lines of hydrogenated protonated naphthalene and proflavine exist. The lines at 281 and 422 nm in the spectrum of the proflavine cation [Bonaca 2010] move to 273 and 454 nm, and three new lines appear between these two in the spectrum of H–C 13 H 11 N + 3 (position I). Rather strong lines exist at 201, 222 and 244 nm.…”

Section: Resultsmentioning

confidence: 99%

“…It has been found that the results of TDDFT calculations (within the Tamm–Dancoff approximation and using the Becke–Lee–Yang–Parr (BLYP) functional) for the excitation energies of several PAH cations agree with experiments to within 0.3 eV (Hirata et al 1999). We have found that calculations with the B3LYP functional (still in development in the latest version of the octopus code) do not change the spectrum of proflavine substantially (Bonaca & Bilalbegović 2010). It has also been found that spectra of proflavine obtained using the time‐propagation method in the octopus code agree with the results of the Lanczos‐chain TDDFT module in Quantum ESPRESSO (Walker et al 2006; Bonaca & Bilalbegović 2010).…”

Section: Methodsmentioning

confidence: 99%

“…We have found that calculations with the B3LYP functional (still in development in the latest version of the octopus code) do not change the spectrum of proflavine substantially (Bonaca & Bilalbegović 2010). It has also been found that spectra of proflavine obtained using the time‐propagation method in the octopus code agree with the results of the Lanczos‐chain TDDFT module in Quantum ESPRESSO (Walker et al 2006; Bonaca & Bilalbegović 2010). It is known that the real‐time propagation method of the octopus code produces the whole optical spectrum up to the far‐UV (Castro et al 2006).…”

Section: Methodsmentioning

confidence: 99%

“…In addition, there is little astronomical interest in the high‐energy region of the spectrum. To facilitate a comparison with other studies of PAHs and organic molecules of astrophysical interest carried out by the same TDDFT method (Malloci, Joblin & Mulas 2007a; Malloci et al 2007b; Bonaca & Bilalbegović 2010; Puletti et al 2010) we show optical spectra up to 6 eV.…”

Section: Methodsmentioning

confidence: 99%

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Electronic absorption spectra of hydrogenated protonated naphthalene and proflavine

Bonaca¹,

Bilalbegović²

2011

Monthly Notices of the Royal Astronomical Society

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We study hydrogenated cations of two polycyclic hydrocarbon molecules as models of hydrogenated organic species that form in the interstellar medium. Optical spectra of the hydrogenated naphthalene cation Hn–C10H+8 for n= 1, 2 and 10, as well as the astrobiologically interesting hydrogenated proflavine cation Hn–C13H11N+3 for n= 1 and 14, are calculated. The pseudopotential time‐dependent density functional theory is used. It is found that the fully hydrogenated proflavine cation H14–C13H11N+3 shows a broad spectrum in which the positions of individual lines are almost lost. The positions, shapes and intensities of lines change in hydronaphthalene and hydroproflavine cations, showing that hydrogen additions induce substantially different optical spectra in comparison with base polycyclic hydrocarbon cations. One calculated line in the visible spectrum of H10–C10H+8 and one in the visible spectrum of H–C13H11N+3 are close to the measured diffuse interstellar bands. We also present the positions of near‐ultraviolet lines.

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The vibronic absorption spectra and electronic states of proflavine in aqueous solution

Kostjukova

Leontieva

Kostjukov

2021

Computational and Theoretical Chemistry

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Optical spectrum of proflavine and its ions

Cited by 8 publications

References 46 publications

Abundances of PAHs in the ISM: confronting observations with experimental results

Abundances of PAHs in the ISM: confronting observations with experimental results

Electronic absorption spectra of hydrogenated protonated naphthalene and proflavine

The vibronic absorption spectra and electronic states of proflavine in aqueous solution

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