A simple effective ∆SCF method for computing optical gap in organic chromophores

2021 ◽  
Author(s):  
Raj Roy ◽  
Abhisek Ghosal ◽  
Amlan K. Roy
Keyword(s):  
Organic Chromophores ◽  
Optical Gap

Narrow optical gap ferroelectric Bi2ZnTiO6 thin films deposited by RF sputtering

2019 ◽  
Vol 7 (17) ◽  
pp. 10696-10701 ◽  
Author(s):  
Fábio G. Figueiras ◽  
J. Ramiro A. Fernandes ◽  
J. P. B. Silva ◽  
Denis O. Alikin ◽  
Eugénia C. Queirós ◽  
...  
Keyword(s):  
Thin Films ◽  
Rf Sputtering ◽  
Optical Gap ◽  
Ferroelectric Oxide

Thriving ferroelectric oxide Bi2ZnTiO6 thin films with a 1.48 eV optical gap.

scholarly journals X-ray transient absorption reveals the 1Au (nπ*) state of pyrazine in electronic relaxation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Valeriu Scutelnic ◽  
Shota Tsuru ◽  
Mátyás Pápai ◽  
Zheyue Yang ◽  
Michael Epshtein ◽  
...  
Keyword(s):  
Electronic Excitation ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Nonadiabatic Dynamics ◽  
X Ray ◽  
Organic Chromophores ◽  
Dynamics Simulations ◽  
X Ray Absorption ◽  
Structure Calculations

AbstractElectronic relaxation in organic chromophores often proceeds via states not directly accessible by photoexcitation. We report on the photoinduced dynamics of pyrazine that involves such states, excited by a 267 nm laser and probed with X-ray transient absorption spectroscopy in a table-top setup. In addition to the previously characterized 1B2u (ππ*) (S2) and 1B3u (nπ*) (S1) states, the participation of the optically dark 1Au (nπ*) state is assigned by a combination of experimental X-ray core-to-valence spectroscopy, electronic structure calculations, nonadiabatic dynamics simulations, and X-ray spectral computations. Despite 1Au (nπ*) and 1B3u (nπ*) states having similar energies at relaxed geometry, their X-ray absorption spectra differ largely in transition energy and oscillator strength. The 1Au (nπ*) state is populated in 200 ± 50 femtoseconds after electronic excitation and plays a key role in the relaxation of pyrazine to the ground state.

Optical Properties of (Pb,Eu)Te Thin Films and Superlattices

1986 ◽  
Vol 89 ◽  
Author(s):  
W. C. Goltsos ◽  
A. V. Nurmikko ◽  
D. L. Partin
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Exchange ◽  
Optical Measurements ◽  
Optical Gap ◽  
Exchange Processes ◽  
Reflectance Measurements

AbstractPhotoluminescence, transmission, and reflectance measurements have yielded information about the states defining an optical gap in thin films and superlattices based on the (Pb,Eu)Te system, including the limit of high Eu concentration. Magneto-optical measurements show the presence of finite spin exchange processes at low Eu-concentrations.

On the optical gap of amorphous silicon

1981 ◽  
Vol 45 (2) ◽  
pp. 289-292 ◽  
Author(s):  
V. Vorlíček ◽  
M. Závětová ◽  
S.K. Pavlov ◽  
L. Pajasová
Keyword(s):  
Amorphous Silicon ◽  
Optical Gap

Optical gap and Urbach edge slope in a-Se

1996 ◽  
Vol 26 (6) ◽  
pp. 279-283 ◽  
Author(s):  
L. Tichý ◽  
H. Tichá ◽  
P. Nagels ◽  
E. Sleeckx ◽  
R. Callaerts
Keyword(s):  
Optical Gap

Optoelectronic Properties of Plasma CVD a-Si:H Modified by Filament-Generated Atomic H

1992 ◽  
Vol 258 ◽  
Author(s):  
Y.M. Li ◽  
I. An ◽  
M. Gunes ◽  
R.M. Dawson ◽  
R.W. Collins ◽  
...  
Keyword(s):  
Film Thickness ◽  
Real Time ◽  
Chemical Potential ◽  
Defect Density ◽  
Plasma Deposition ◽  
Plasma Cvd ◽  
Near Surface ◽  
Optical Gap ◽  
New Material ◽  
Control Samples

ABSTRACTWe have studied a-Si:H prepared by alternating plasma deposition with atomic H treatments performed with a heated W filament. Real time spectroscopie ellipsometry provides the evolution of film thickness, optical gap, and a measure of the fraction of Si-Si bonds broken in the near-surface (200 Å) during H-exposure of single films. This information guided us to the desired parameters for the H-treatments. Here, we concentrate on a weak hydrogenation regime characterized by minimal etching, a higher H content by 2 at.%, and a larger optical gap by 0.02 eV for the growth/hydrogenation structures in comparison to continuously deposited control samples. This new material has shown an improvement in the defect density in the light-soaked state in comparison to the control samples. This may result from stabilization of the Si structure due to an increase in the H chemical potential in the a-Si:H.

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