Excited states and excitonic interactions in prototypic polycyclic aromatic hydrocarbon dimers as models for graphitic interactions in carbon dots

2019 ◽  
Vol 21 (18) ◽  
pp. 9077-9088 ◽  
Author(s):  
Baimei Shi ◽  
Dana Nachtigallová ◽  
Adélia J. A. Aquino ◽  
Francisco B. C. Machado ◽  
Hans Lischka
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Excited States ◽  
Carbon Dots ◽  
Polycyclic Aromatic ◽  
Excitonic Interactions ◽  
Homo Lumo

The HOMO–LUMO transition in a stacked circum-1-coronene dimer as a model for excimer interactions in carbon dots.

scholarly journals Electronically Excited States of Closed-Shell, Cyano-Functionalized Polycyclic Aromatic Hydrocarbon Anions

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 296-313
Author(s):  
Taylor J. Santaloci ◽  
Ryan C. Fortenberry
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Excited States ◽  
Oscillator Strengths ◽  
State Transitions ◽  
Electronically Excited States ◽  
Absorption And Emission ◽  
Electronically Excited ◽  
Polycyclic Aromatic ◽  
Absorption Features

Few anions exhibit electronically excited states, and, if they do, the one or two possible excitations typically transpire beyond the visible spectrum into the near-infrared. These few, red-shifted electronic absorption features make anions tantalizing candidates as carriers of the diffuse interstellar bands (DIBs), a series of mostly unknown, astronomically ubiquitous absorption features documented for over a century. The recent interstellar detection of benzonitrile implies that cyano-functionalized polycyclic aromatic hydrocarbon (PAH) anions may be present in space. The presently reported quantum chemical work explores the electronic properties of deprotonated benzene, naphthalene, and anthracene anions functionalized with a single cyano group. Both the absorption and emission properties of the electronically excited states are explored. The findings show that the larger anions absorption and emission energies possess both valence and dipole bound excitations in the 450–900 nm range with oscillator strengths for both types of >1×10−4. The valence and dipole bound excited state transitions will produce slightly altered substructure from one another making them appear to originate with different molecules. The known interstellar presence of related molecules, the two differing natures of the excited states for each, and the wavelength range of peaks for these cyano-functionalized PAH anions are coincident with DIB properties. Finally, the methods utilized appear to be able to predict the presence of dipole-bound excited states to within a 1.0 meV window relative to the electron binding energy.

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

Karakterisasi Komponen Aktif Asap Cair Cangkang Sawit Hasil Pemurnian

2016 ◽  
Vol 9 (1) ◽  
pp. 64-72
Author(s):  
Fauziati Fauziati ◽  
Eldha Sampepana
Keyword(s):  
Acetic Acid ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Activated Charcoal ◽  
Oil Refining ◽  
Gas Chromatography Mass Spectrometry ◽  
Antioxidant Compounds ◽  
Active Components ◽  
Liquid Smoke ◽  
Polycyclic Aromatic

Palm shell liquid smoke obtained by pyrolysis and redestilasi still produce a pungent smoke flavor and color of yellow to brownish yellow so that the necessary research purification of smoke that can be used as ingredients other than preservatives, such as antiseptic hand wash. The research objective is to reduce the stinging liquid smoke aroma, color is tawny and to identify the characterization of the active components of liquid smoke shell oil refining results in Gas Chromatography Mass Spectrometry (GC-MS). The purification process of liquid smoke with redistilled at a temperature of 2000C and by adding 4.5% zeolite adsorbent made three (3) times the resulting liquid smoke of distillate and residue. Liquid smoke produced from distillate and residue are added activated charcoal as much as 9%, 10.5% and 12%, then stirred with a shaker subsequently allowed to stand for 6 days and 10 days The results of the study showed that liquid smoke purification results of the residue by the addition of activated charcoal as 12% and the time saved for 10 days (A2B2C3) gives flavor and color by 1.94 of 1.84 is odorless, yellowish white color and clarity. While the characteristics of the active components of purification results are predominantly acetic acid and phenol compounds of residues that serve as preservatives, antibacterial and antioxidant compounds while PAH (Polycyclic Aromatic Hydrocarbon), namely tar, benzoperen, gualakol and siringoll (aroma causes) undetectedABSTRAKAsap cair cangkang sawit yang diperoleh melalui proses pirolisis dan redestilasi masih menghasilkan aroma asap menyengat dan warna kuning hingga kuning kecoklatan sehingga diperlukan penelitian pemurnian asap yang dapat digunakan sebagai bahan lain selain pengawet, seperti antiseptik pencuci tangan. Tujuan penelitian adalah  untuk mengurangi aroma asap cair yang menyengat, warna yang masih kuning kecoklatan dan untuk  mengidentifikasi karakterisasi komponen aktif asap cair cangkang sawit hasil pemurnian secara Kromatografi Gas Spektrometri Massa (GC-MS). Proses  pemurnian asap cair dengan  redistilasi pada suhu 2000C dan dengan menambahkan adsorben zeolit 4,5% yang dilakukan sebanyak 3 (tiga) kali  dihasilkan asap cair dari Destilat dan Residu . Asap cair  yang dihasilkan dari destilat dan residu ditambahkan arang aktif sebanyak 9%,10,5% dan 12%  kemudian diaduk dengan shaker selanjutnya didiamkan selama 6 hari dan 10 hari .Hasil penelitian menunjukkan bahwa asap cair hasil pemurnian dari residu dengan penambahan arang aktif sebanyak 12% dan waktu simpan selama 10 hari ( A2B2C3 ) memberikan aroma sebesar 1,94 dan warna sebesar 1,84 adalah tidak berbau ,  warna putih kekuningan dan jernih . Sedangkan  karakteristik  komponen aktif hasil pemurnian yang paling dominan  adalah  senyawa acetic acid dan phenol  dari residu yang berfungsi sebagai bahan pengawet, antibakteri dan antioksidan sedangkan senyawa PAH (Polycyclic Aromatic Hydrocarbon) yaitu tar, benzoperen,  gualakol  dan siringoll ( penyebab aroma ) tidak terdeteksi . Kata kunci : asap cair, cangkang sawit, komponen aktif, pemurnian, redestilasi 

DISCHARGE WATERS: DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBON (PAH) LEVELS BY A GC-MS/MS METHOD

2015 ◽  
Vol 14 (5) ◽  
pp. 1195-1202 ◽  
Author(s):  
Nadia Crini ◽  
Coline Druart ◽  
Caroline Amiot ◽  
Sophie Gavoille ◽  
Gregorio Crini
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Polycyclic Aromatic

Multiple Fused Anthracenes as Helical Polycyclic Aromatic Hydrocarbon Motif for Chiroptical Performance Enhancement

2020 ◽  
Vol 15 (16) ◽  
pp. 2456-2461 ◽  
Author(s):  
Kei Fujise ◽  
Eiji Tsurumaki ◽  
Gaku Fukuhara ◽  
Nobuyuki Hara ◽  
Yoshitane Imai ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Performance Enhancement ◽  
Polycyclic Aromatic
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