Multiphoton ionization and dissociation of polycyclic aromatic hydrocarbon molecules of astrophysical interest

Chacko, Roby; Barik, Saroj; Banhatti, Shreyak; Aravind, G.

doi:10.1103/physreva.105.032804

Cited by 3 publications

(4 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…that may contaminate the target when firing the light gas gun exhibit minimal autofluorescence (see Figure S2). Moreover, according to Chacko and co-workers, the UV-induced chemical degradation of phenanthrene produces relatively small nonaromatic molecular/atomic fragments that are unlikely to exhibit any autofluorescence . Thus, if autofluorescence is observed in the vicinity of impact craters, this should be a useful signature for phenanthrene survival after impact.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, according to Chacko and co-workers, the UV-induced chemical degradation of phenanthrene produces relatively small nonaromatic molecular/atomic fragments that are unlikely to exhibit any autofluorescence. 25 Thus, if autofluorescence is observed in the vicinity of impact craters, this should be a useful signature for phenanthrene survival after impact. In principle, this is a significant improvement on the analytical X-ray mapping capability used in conjunction with SEM analysis reported in our prior study.…”

Section: Resultsmentioning

confidence: 99%

“…Phenanthrene and anthracene comprise the two simplest examples of PAHs: they are structural isomers with an identical atomic mass of 178.23 g mol –1 (see Figure ). Interestingly, recent literature − suggests that these two compounds may exhibit subtly different mass fragmentation patterns during impact ionization when impinging on metal targets at >1 km s –1 . Our preparation of micron-sized anthracene microparticles via wet ball milling was conducted in the presence of Morwet D-425, a commercially available anionic water-soluble polymer (see Figure b) .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis of Autofluorescent Phenanthrene Microparticles via Emulsification: A Useful Synthetic Mimic for Polycyclic Aromatic Hydrocarbon-Based Cosmic Dust

Chan,

Wills,

Tandy

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Phenanthrene is the simplest example of a polycyclic aromatic hydrocarbon (PAH). Herein, we exploit its relatively low melting point (101 °C) to prepare microparticles from molten phenanthrene droplets by conducting high-shear homogenization in a 3:1 water/ethylene glycol mixture at 105 °C using poly(N-vinylpyrrolidone) as a non-ionic polymeric emulsifier. Scanning electron microscopy studies confirm that this protocol produces polydisperse phenanthrene microparticles with a spherical morphology: laser diffraction studies indicate a volume-average diameter of 25 ± 21 μm. Such projectiles are fired into an aluminum foil target at 1.87 km s–1 using a two-stage light gas gun. Interestingly, the autofluorescence exhibited by phenanthrene aids analysis of the resulting impact craters. More specifically, it enables assessment of the spatial distribution of any surviving phenanthrene in the vicinity of each crater. Furthermore, these phenanthrene microparticles can be coated with an ultrathin overlayer of polypyrrole, which reduces their autofluorescence. In principle, such core–shell microparticles should be useful for assessing the extent of thermal ablation that is likely to occur when they are fired into aerogel targets. Accordingly, polypyrrole-coated microparticles were fired into an aerogel target at 2.07 km s–1. Intact microparticles were identified at the end of carrot tracks and their relatively weak autofluorescence suggests that thermal ablation during aerogel capture did not completely remove the polypyrrole overlayer. Thus, these new core–shell microparticles appear to be useful model projectiles for assessing the extent of thermal processing that can occur in such experiments, which have implications for the capture of intact PAH-based dust grains originating from cometary tails or from plumes emanating from icy satellites (e.g., Enceladus) in future space missions.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of Autofluorescent Phenanthrene Microparticles via Emulsification: A Useful Synthetic Mimic for Polycyclic Aromatic Hydrocarbon-Based Cosmic Dust

Chan,

Wills,

Tandy

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

show abstract

“…Molecular mass growth mechanisms involving ion-molecule collisions require ionizing radiations, which are scarce in the interiors of these dense clouds. The growth of PANHs in photodestructive ISMs remains a paradox (20)(21)(22)(23). The detection of advanced biomolecules in meteorites, with PANHs as the precursors, implies the existence of molecular mass growth mechanisms that efficiently compete with the photodestruction rates.…”

Section: Introductionmentioning

confidence: 99%

Molecular growth of PANH via intermolecular Coulombic decay

et al. 2023

Self Cite

View full text Add to dashboard Cite

Nitrogen-bearing polycyclic aromatic hydrocarbons (PANHs) are ubiquitous in space. They are considered precursors to advanced biomolecules identified in meteorites. However, their chemical evolution into biomolecules in photodestructive astrophysical mediums remains a paradox. Here, we show that light can efficiently initiate the molecular mass growth of PANHs. Ultraviolet-photoexcited quinoline monomers, the smallest PANH, were observed to associate and intermolecular Coulombic decay between the associating monomers formed the cations of quinoline-dimer. Molecular rearrangements in the dimer cation lead to a dominant formation of cations heavier than quinoline. The enrichment of these heavier cations over all the other cations reveals the efficiency of this route for the mass growth of PANHs in space. This mechanism also leads to a highly reactive unsaturated PANH-ring via CH loss, a hitherto unknown channel in any photon-driven process. The occurrence of this efficient pathway toward complex molecules points to a rich chemistry in dense interstellar clouds.

show abstract

A comparative laboratory study of soft X-ray-induced ionization and fragmentation of five small PAH cations

Huo,

Cangahuala,

Zamudio-Bayer

et al. 2023

Eur. Phys. J. D

View full text Add to dashboard Cite

The interaction between polycyclic aromatic hydrocarbon (PAH) radical cations and X-rays predominantly leads to photofragmentation, a process that strongly depends on PAH size and geometry. In our experiments, five prototypical PAHs were exposed to monochromatic soft X-ray photons with energies in the C K-edge regime. As a function of soft X-ray photon energy, photoion yields were obtained by means of time-of-flight mass spectrometry. The resulting near-edge X-ray absorption mass spectra were interpreted using time-dependent density functional theory (TD-DFT) with a short-range corrected functional. We found that the carbon backbone of anthracene$$^+$$ + (C$$_{14}$$ 14 H$$_{10}^+$$ 10 + ), pyrene$$^+$$ + (C$$_{16}$$ 16 H$$_{10}^+$$ 10 + ) and coronene$$^+$$ + (C$$_{24}$$ 24 H$$_{12}^+$$ 12 + ) can survive soft X-ray absorption, even though mostly intermediate size fragments are formed. In contrast, for hexahydropyrene$$^+$$ + (C$$_{16}$$ 16 H$$_{16}^+$$ 16 + ) and triphenylene$$^+$$ + (C$$_{18}$$ 18 H$$_{12}^+$$ 12 + ) molecular survival is not observed and the fragmentation pattern is dominated by small fragments. For a given excitation energy, molecular survival evidently does not simply correlate with PAH size but strongly depends on other PAH properties. Graphic abstract

show abstract

Multiphoton ionization and dissociation of polycyclic aromatic hydrocarbon molecules of astrophysical interest

Cited by 3 publications

References 64 publications

Synthesis of Autofluorescent Phenanthrene Microparticles via Emulsification: A Useful Synthetic Mimic for Polycyclic Aromatic Hydrocarbon-Based Cosmic Dust

Synthesis of Autofluorescent Phenanthrene Microparticles via Emulsification: A Useful Synthetic Mimic for Polycyclic Aromatic Hydrocarbon-Based Cosmic Dust

Molecular growth of PANH via intermolecular Coulombic decay

A comparative laboratory study of soft X-ray-induced ionization and fragmentation of five small PAH cations

Contact Info

Product

Resources

About