Molecular Structures and Absorption Spectra Assignment of Corrole NH Tautomers

2014 ◽  
Vol 118 (5) ◽  
pp. 862-871 ◽  
Author(s):  
Wichard Beenken ◽  
Martin Presselt ◽  
Thien H. Ngo ◽  
Wim Dehaen ◽  
Wouter Maes ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Molecular Structures

A theoretical investigation of tetrahydroquinoline dyes with different spacers used for sensitized solar cells

2011 ◽  
Vol 89 (8) ◽  
pp. 978-986 ◽  
Author(s):  
Jie Xu ◽  
Lei Wang ◽  
Li Liu ◽  
Zikui Bai ◽  
Luoxin Wang ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Photovoltaic Performance ◽  
Molecular Structures ◽  
Absorption Bands ◽  
Functional Theory ◽  
Spacer Length ◽  
Solvent Interaction ◽  
Td Dft ◽  
Sensitized Solar Cells

The molecular structures and absorption spectra of three tetrahydroquinoline dyes (C2–1, C1–1, and C1–5) with a tetrahydroquinoline moiety as the electron donor, a cyanoacrylic acid moiety as the electron acceptor, and different thiophene-containing electron spacers were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT). The calculated geometries indicate that a strong conjugation is formed in the dyes and the conjugate length increases with the increase of spacer length. The interfacial charge transfer between the semiconductor electrode and the tetrahydroquinoline dyes are electron-injection processes from the excited dyes to the semiconductor conduction band. The simulated absorption bands are assigned to π–π* transitions, which exhibit appreciable red-shift with respect to the experimental bands owing to the lack of direct solute–solvent interaction and the inherent approximations in TD-DFT. Moreover, the effect of different spacers on the molecular structures, absorption spectra, and photovoltaic performance were comparatively discussed.

Regioisomeric synthesis of chlorin-e6 dimethyl esters and their optical properties

2018 ◽  
Vol 22 (12) ◽  
pp. 1039-1046 ◽  
Author(s):  
Yasunobu Nagano ◽  
Shin Ogasawara ◽  
Hitoshi Tamiaki
Keyword(s):  
Optical Properties ◽  
Absorption Spectra ◽  
Carboxy Group ◽  
Fluorescence Emission ◽  
Substitution Effect ◽  
Molecular Structures ◽  
Chlorin E6 ◽  
Visible Absorption ◽  
Methyl Esterification ◽  
Hydrolysis Of

Chlorin-[Formula: see text] dimethyl esters possessing a single carboxy group at the 13-, 151-, or 172-position were prepared by chemically modifying chlorophyll-[Formula: see text]. These three synthetic regioisomers were fully characterized by their mass, NMR, and visible absorption spectra. Their molecular structures were unambiguously identified by the specific 1H–[Formula: see text]C correlation at the 13-, 15-, and/or 17-substituents in their respective HMBC spectra. Methyl esterification of 13/151-COOH and hydrolysis of 13/151-COOMe affected small shifts of the Qy absorption and fluorescence emission maxima in a diluted CH2Cl2 solution, while no substitution effect of 172-COOH/Me was observed.

scholarly journals Density Functional Theory Study on the Electronic Structures of Oxadiazole Based Dyes as Photosensitizer for Dye Sensitized Solar Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Umer Mehmood ◽  
Ibnelwaleed A. Hussein ◽  
Khalil Harrabi ◽  
Shakeel Ahmed
Keyword(s):  
Density Functional Theory ◽  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Dye Sensitized Solar Cells ◽  
Electron Injection ◽  
Molecular Structures ◽  
Visible Absorption ◽  
Functional Theory ◽  
Oxidation Potentials

The molecular structures and UV-visible absorption spectra of complex photosensitizers comprising oxadiazole isomers as theπ-bridges were analyzed by density functional theory (DFT) and time-dependent DFT. The ground state and excited state oxidation potentials, HOMOs and LUMOs energy levels, and electron injection from the dyes to semiconductor TiO2have been computed in vacuum here. The results show that all of the dyes may potentially be good photosensitizers in DSSC. To justify the simulation basis, N3 dye was also simulated under the similar conditions. Simulated absorption spectrum, HOMO, LUMO, and band gap values of N3 were compared with the experimental values. We also computed the electronic structure properties and absorption spectra of dye/(TiO2)8systems to elucidate the electron injection efficiency at the interface. This work is expected to give proper orientation for experimental synthesis.

scholarly journals XABOOM: An X-Ray Absorption Benchmark of Organic Molecules Based on Carbon, Nitrogen, and Oxygen 1s → π ∗ Transitions

2021 ◽  
Author(s):  
Thomas Fransson ◽  
Iulia Emilia Brumboiu ◽  
Marta L. Vidal ◽  
Patrick Norman ◽  
Sonia Coriani ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Organic Molecules ◽  
Molecular Structures ◽  
X Ray ◽  
Benchmark Study ◽  
X Ray Absorption

Presenting a benchmark study on calculating X-ray absorption spectra, named XABOOM (X-ray absorption<br>benchmark of organic molecules), comparing the performance for considering 1s → π ∗ transitions using ADC, CC, TDDFT, and TP-DFT. Molecular structures and spectroscopic data is provided.<br>

scholarly journals The absorption spectra of polyatomic molecules containing methyl and ethyl radicals—III

1936 ◽  
Vol 156 (887) ◽  
pp. 108-129 ◽  
Keyword(s):  
Absorption Spectra ◽  
Ultra Violet ◽  
Close Packing ◽  
Polyatomic Molecules ◽  
Molecular Structures ◽  
Continuous Absorption ◽  
Symmetry Properties ◽  
Photochemical Decomposition ◽  
The One ◽  
Wave Limit

The study of the absorption spectra of simple polyatomic molecules has many objects. As for diatomic molecules, it may lead to a deeper understanding of the interpretation of the spectra of polyatomic molecules in terms of spectral theory. As a consequence it may also lead to chemical data such as the energies of linkage, interatomic distances, and the electronic configurations of the molecules. In addition, it may help to explain the mechanism and nature of the primary processes in photochemical decomposition. In passing from diatomic to polyatomic molecules, however, two additional matters become of importance: on the one hand, the nature and types of vibration (valency or deformation, symmetrical or antisymmetrical) induced by the electronic excitation are of interest, and, on the other, it is desirable to examine how far symmetry properties assumed on the basis of independently determined molecular structures are borne out in the structure of their spectra. The difficulties in these studies are not solely due to the often very complicated structure of polyatomic molecule spectra, but also frequently to the continuous nature of these spectra in the ultra-violet region. It is with this region of absorption that photochemical considerations are usually concerned, the frequencies associated with it corresponding to transitions between the lower electronic states of the molecules. The interpretation of the continua is at the present time far from clear. In some cases work at low pressures reveals the existence of bands which so merge together with increasing pressure as to give effectively continuous absorption, whilst in other cases where the continua are apparently genuine, the influence of pressure upon the long wave limit of absorption is considerable. Even the conclusions to be drawn from the diffuse nature of the bands with polyatomic molecules are usually ambiguous, since it is not certain whether true cases of "predissociation" are involved or whether the large moments of inertia lead to unresolved close packing of rotational lines.

Sign in / Sign up

Export Citation Format

Share Document