Molecular Packing-Dependent Exciton and Polariton Dynamics in Anthradithiophene Organic Crystals

MRS Advances ◽  
2018 ◽  
Vol 3 (59) ◽  
pp. 3465-3470 ◽  
Author(s):  
Jonathan D B Van Schenck ◽  
Gregory Giesbers ◽  
Akash Kannegulla ◽  
Li-Jing Cheng ◽  
John E. Anthony ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Energy Absorption ◽  
Absorption Spectra ◽  
Organic Crystals ◽  
Optical Microcavities ◽  
Enhanced Absorption ◽  
Excitonic Transition ◽  
Dependent Absorption ◽  
Derivatives Of ◽  
Primary Contribution

AbstractPolarization-dependent absorption spectra of two functionalized derivatives of fluorinated anthradithiophene, diF TES-ADT and diF TDMS-ADT, were studied in the crystal phase using a Holstein-like Hamiltonian. For both molecules, the primary contribution to the lowest energy absorption was found to be the S0-S1 excitonic transition perturbed by an intermolecular coupling of 15 meV for both TES and TDMS. A secondary contribution, consistent with that from charge-transfer states, was also found. Additionally, absorption spectra were analysed when crystals were placed inside of optical microcavities formed by two metal mirrors. Cavities exhibited a primary absorption peak determined to be an enhanced absorption from the lowest-energy S0-S1 transition.

scholarly journals Coloration of Flowers by Flavonoids and Consequences of pH Dependent Absorption

2021 ◽  
Vol 11 ◽  
Author(s):  
Doekele G. Stavenga ◽  
Hein L. Leertouwer ◽  
Bettina Dudek ◽  
Casper J. van der Kooi
Keyword(s):  
Absorption Spectra ◽  
Ph Dependence ◽  
Bathochromic Shift ◽  
Flower Color ◽  
Color Evolution ◽  
Dependent Absorption ◽  
Ph Dependent ◽  
Basic States ◽  
Pigment Absorption ◽  
Derivatives Of

Flavonoid pigments are key determinants of flower colors. As absorption spectra of flavonoids are known to be severely pH-dependent, cellular pH will play a crucial role in flower coloration. The flavonoids are concentrated in the vacuoles of the flowers’ epidermal cells, and thus the pigments’ absorption spectra are modulated by the vacuolar pH. Here we study the pH dependence of flavonoid absorption spectra in extracts from flowers of two poppy species Papaver dubium (red) and Meconopsis cambrica (orange), and a white and red Mandevilla sanderi variety. In the red poppy and Mandevilla flowers, absorption spectra of the cyanidin- and pelargonidin-based anthocyanins peak in the blue-green-wavelength range at low pH, but exhibit a distinct bathochromic shift at higher pH. This shift to longer wavelengths is not found for the blue-absorbing nudicaulin derivatives of M. cambrica, which have a similar absorption spectrum at low and high pH. The pH-dependent absorption changes of the white M. sanderi’s flavonoid remained restricted to the UV. An analysis of the spectra with logistic functions suggests that the pH-dependent characteristics of the basic states of flavonols and anthocyanins are related. The implications of tuning of pH and pigment absorption spectra for studies on flower color evolution are discussed.

Macrocyclic dipyrrin dimer bridged by ethylene and dioxyphenylene linkers

2015 ◽  
Vol 19 (01-03) ◽  
pp. 135-139 ◽  
Author(s):  
Ji-Young Shin ◽  
Satoru Hiroto ◽  
Hiroshi Shinokubo
Keyword(s):  
Charge Transfer ◽  
Diffraction Analysis ◽  
Absorption Spectra ◽  
Intramolecular Charge Transfer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dependent Absorption

A tetrapyrrolic macrocycle containing ethenylene and dioxyphenylene bridges was obtained through the reaction of a dipyrrin-DDQ adduct with triethylamine. The structure of the macrocycle was elucidated by X-ray diffraction analysis. The macrocycle exhibited solvent-dependent absorption spectra due to intramolecular charge transfer interactions.

scholarly journals Association-dependent absorption spectra of oxyhemoglobin A and its subunits.

1981 ◽  
Vol 256 (15) ◽  
pp. 7917-7924 ◽  
Author(s):  
J.S. Philo ◽  
M.L. Adams ◽  
T.M. Schuster
Keyword(s):  
Absorption Spectra ◽  
Dependent Absorption

scholarly journals A broadband optical cavity spectrometer for measuring weak near-ultraviolet absorption spectra of gases

2011 ◽  
Vol 4 (3) ◽  
pp. 425-436 ◽  
Author(s):  
J. Chen ◽  
D. S. Venables
Keyword(s):  
Absorption Spectra ◽  
Cross Sections ◽  
Optical Cavity ◽  
Absorption Cross ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
Near Ultraviolet ◽  
Low Concentrations ◽  
Measured Absorption ◽  
Atmospheric Observations

Abstract. Accurate absorption spectra of gases in the near–ultraviolet (300 to 400 nm) are essential in atmospheric observations and laboratory studies. This paper describes a novel incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instrument for measuring very weak absorption spectra from 335 to 375 nm. The instrument performance was validated against the 3B1-X1A1 transition of SO2. The measured absorption varied linearly with SO2 column density and the resulting spectrum agrees well with published spectra. Using the instrument, we report new absorption cross-sections of O3, acetone, 2-butanone, and 2-pentanone in this spectral region, where literature data diverge considerably. In the absorption minimum between the Huggins and Chappuis bands, our absorption spectra fall at the lower range of reported ozone absorption cross-sections. The spectra of the ketones agree with prior spectra at moderate absorptions, but differ significantly at the limits of other instruments' sensitivity. The collision-induced absorption of the O4 dimer at 360.5 nm was also measured and found to have a maximum cross-section of ca. 4.0×10−46 cm5 molecule−2. We demonstrate the application of the instrument to quantifying low concentrations of the short-lived radical, BrO, in the presence of stronger absorptions from Br2 and O3.

scholarly journals Энергетический спектр и оптическое поглощение эндоэдральных комплексов Er-=SUB=-2-=/SUB=-C-=SUB=-2-=/SUB=-@C-=SUB=-90-=/SUB=- на основе изомеров N 21 и N 44

2021 ◽  
Vol 129 (9) ◽  
pp. 1111
Author(s):  
А.И. Мурзашев ◽  
А.П. Жуманазаров ◽  
М.Ю. Кокурин
Keyword(s):  
Experimental Data ◽  
Charge Transfer ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Coulomb Interaction ◽  
Energy Spectra ◽  
Optical Absorption Spectra ◽  
Endohedral Complexes

The article simulates the optical absorption spectra (OAS) of endohedral complexes Er2C2 @ C90 based on isomers No. 44 (C2) No. 21 (C1) of fullerene C90. For this purpose, the energy spectra of the indicated isomers have been calculated. The calculation was carried out within the framework of two models. Within the framework of the first model, which is traditional, only hops of π-electrons from site to site were taken into account (the integral of hopping to the nearest sites B ~ -2.6 eV). Within the framework of the second model, developed in a series of our works [1-5], in addition to hopping from site to site (the integral of hopping to the nearest sites B ~ -1.0 eV), the intrasite Coulomb interaction (ICCI) of π-electrons was also taken into account (the integral of the Coulomb interaction U ~ 7.0 eV). Comparison of the OSS curves obtained by us with the experimental data [5] convincingly indicates that the second model adequately describes the OSS of the endohedral Er2C2 @ C90 complexes based on the investigated isomers. The magnitude of charge transfer from the Er2C2 system to the fullerene shell turned out to be -4e.

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