scholarly journals Interstellar polycyclic aromatic hydrocarbons: Spectroscopy, photofragmentation and photoproducts

2019 ◽  
Vol 15 (S350) ◽  
pp. 353-355
Author(s):  
Jordy Bouwman ◽  
Jerry Kamer ◽  
Pablo Castellanos ◽  
Michał Bulak ◽  
Sanjana Panchagnula ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Ion Trap ◽  
Infrared Emission ◽  
Functional Theory ◽  
Mid Infrared ◽  
Radiation Fields ◽  
Polycyclic Aromatic ◽  
Spectroscopic Signatures

AbstractUbiquitous strong mid-infrared emission bands are observed towards many objects and are attributed to interstellar Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are ionized, or even dissociate, when exposed to strong interstellar radiation fields. By means of ion trap mass spectrometry, light-induced dissociation patterns of PAH cations are measured and the mid-infrared spectroscopic signatures of the parent ion and its dissociation products are characterized. These results are then combined with density functional theory (DFT) calculations to obtain insight into the dissociation characteristics of interstellar PAHs at a molecular level.

scholarly journals Binding of polycyclic aromatic hydrocarbons and graphene dimers in density functional theory

2010 ◽  
Vol 12 (1) ◽  
pp. 013017 ◽  
Author(s):  
Svetla D Chakarova-Käck ◽  
Aleksandra Vojvodic ◽  
Jesper Kleis ◽  
Per Hyldgaard ◽  
Elsebeth Schröder
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Functional Theory ◽  
Polycyclic Aromatic

scholarly journals Optoelectronic Properties of Polycyclic Aromatic Hydrocarbons of Various Sizes and Shapes: A DFT Study

2020 ◽  
Author(s):  
Ramachandran Rakhi ◽  
Cherumuttathu H Suresh
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Optoelectronic Properties ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Practical Applications ◽  
Td Dft ◽  
Polycyclic Aromatic ◽  
Electron Withdrawing Group

Polycyclic aromatic hydrocarbons (PAHs) can be considered as graphene nanoflakes in which the edges are hydrogenated. Zigzag and armchair-edged PAHs possessing circular, parallelogram, rectangular and triangular shapes have been studied using M06L/6-31+G(d) level of density functional theory (DFT). Molecular electrostatic potential (MESP) analysis of the PAHs is done to characterize their electron distribution while the time-dependent DFT (TD-DFT) analysis was used for the absorption spectral analysis. MESP analysis clearly showed Clar’s sextet like electronic arrangement in armchair-edged systems whereas zigzag-edged ones showed significant electron localization towards the edges. TD-DFT analysis casts light upon the absorption features of these systems, which followed a linear trends in absorption maximum (lmax) for most of the armchair-edged systems with respect to the number of π-electrons. MESP analysis on the electron rich and electron deficient features of PAH systems led to the design of donor-spacer-acceptor type PAH-π-PAH systems (D-π-A systems) wherein a conjugated diene moiety functions as the π-spacer. Though these systems behaved weakly as D-π-A systems, with the introduction of electron donating functional group NMe2 on one PAH and electron withdrawing group COOH on the other led to the formation of strong D-π-A systems.  The MESP features, frontier molecular orbital (FMO) distribution, and absorption spectral features supported their strong D-π-A character. Among the different shapes studied, the rectangular PAH moiety showed the most efficient tuning of HOMO-LUMO gap. The optical and electronic data of PAH, PAH-π-PAH and functionalized PAH-π-PAH systems shed light upon possible tuning of their optoelectronic properties for practical applications.

Bowl-to-bowl inversion of sumanene derivatives

2012 ◽  
Vol 84 (4) ◽  
pp. 1089-1100 ◽  
Author(s):  
Toru Amaya ◽  
Toshikazu Hirao
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Dft Calculation ◽  
Functional Theory ◽  
Ongoing Research ◽  
Benzene Rings ◽  
Polycyclic Aromatic ◽  
Anion Species

Bowl-to-bowl inversion is one of the characteristic behaviors for some flexible open-end molecular bowls consisting of polycyclic aromatic hydrocarbons with benzene rings fused by imbedded five-membered rings (π bowls). This intriguing dynamics was studied with sumanene, which is the smallest C3v symmetric fragment of fullerenes. In this article, our ongoing research on the bowl-to-bowl inversion of sumanene, its benzylic anion species, hexasubstituted derivatives, mononaphthosumanene, and [CpRu(η6-sumenene)]+ complex is summarized. Estimation based on density functional theory (DFT) calculation is also described.

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