Effect of cation off-stoichiometry on optical absorption in epitaxial LaFeO3 films

2017 ◽  
Vol 19 (16) ◽  
pp. 10371-10376 ◽  
Author(s):  
Mark D. Scafetta ◽  
Steven J. May
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Optical Absorption ◽  
Optical Absorption Spectrum ◽  
Defect Chemistry ◽  
Epitaxial Films ◽  
Perovskite Oxide ◽  
Cation Deficiency ◽  
The Relationship

The effect of A- and B-site cation deficiency on the optical absorption spectrum is presented for a series of LaFeO3−δ epitaxial films providing insights into the relationship between defect chemistry and electronic structure in this semiconducting perovskite oxide.

ENERGY STATES IN QUANTUM DOTS

2002 ◽  
Vol 12 (01) ◽  
pp. 15-43 ◽  
Author(s):  
ANDREW J. WILLIAMSON
Keyword(s):  
Quantum Dots ◽  
Absorption Spectrum ◽  
Electronic Structure ◽  
Optical Absorption ◽  
Configuration Interaction ◽  
Single Particle ◽  
Optical Absorption Spectrum ◽  
Semiconductor Quantum Dots ◽  
Binding Energies ◽  
Particle Level

We describe a procedure for calculating the electronic structure of semiconductor quantum dots containing over one million atoms. The single particle electron levels are calculated by solving a Hamiltonian constructed from screened atomic pseudopotentials. Effects beyond the single particle level such as electron and hole exchange and correlation interactions are described using a configuration interaction (CI) approach. Application of these methods to the calculation of the optical absorption spectrum, Coulomb repulsions and multi-exciton binding energies of InGaAs self-assembled quantum dots are presented.

Electronic Structure and Optical Absorption of Fluorographene

2011 ◽  
Vol 1370 ◽  
Author(s):  
Yufeng Liang ◽  
Li Yang
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Charge Transfer ◽  
Optical Absorption ◽  
Optical Absorption Spectrum ◽  
First Principles ◽  
Gw Approximation ◽  
Exciton Condensation ◽  
Excitonic Effects ◽  
Electron Effects

ABSTRACTA first-principles study on the quasiparticles energy and optical absorption spectrum of fluorographene is presented by employing the GW + Bethe-Salpeter Equation (BSE) method with many-electron effects included. The calculated band gap is increased from 3.0 eV to 7.3 eV by the GW approximation. Moreover, the optical absorption spectrum of fluorographene is dominated by enhanced excitonic effects. The prominent absorption peak is dictated by bright resonant excitons around 9.0 eV that exhibit a strong charge transfer character, shedding light on the exciton condensation and relevant optoelectronic applications. At the same time, the lowest-lying exciton at 3.8 eV with a binding energy of 3.5 eV is identified, which gives rise to explanation of the recent ultraviolet photoluminescence experiment.

CLUSTER CALCULATION OF THE ELECTRONIC STRUCTURE OF K3C60

1995 ◽  
Vol 09 (02) ◽  
pp. 95-101 ◽  
Author(s):  
KALINE COUTINHO ◽  
SYLVIO CANUTO ◽  
A. FAZZIO ◽  
R. MOTA
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Optical Absorption ◽  
Density Of States ◽  
Optical Absorption Spectrum ◽  
Cluster Calculation ◽  
Metallic System ◽  
Calculated Density ◽  
Inverse Photoemission ◽  
Molecular Orbital Model

A cluster with 188 atoms is utilized to investigate the electronic structure of K 3 C 60 within the molecular orbital model. The calculated density of states is in excellent agreement with experimental results of photoemission and inverse photoemission. The band gap is calculated using three different schemes and the results indicate a metallic system. The optical absorption spectrum is calculated from a CI procedure and indicates transitions below 15000 cm –1 not present in pristine C 60.

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 411-413
Author(s):  
Yixing Zhao ◽  
Gordon R Freeman
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Temperature Dependence ◽  
Optical Absorption Spectrum ◽  
Infrared Light ◽  
Solvated Electron ◽  
Solvated Electrons ◽  
Tert Butanol ◽  
Solvent Dependence ◽  
Increasing Temperature

The energy and asymmetry of the optical absorption spectrum of solvated electrons, es- , change in a nonlinear fashion on changing the solvent through the series HOH, CH3OH, CH3CH3OH, (CH3)2CHOH, (CH3)3COH. The ultimate, quantum-statistical mechanical, interpretation of solvated electron spectra is needed to describe the solvent dependence. The previously reported optical spectrum of es- in tert-butanol was somewhat inaccurate, due to a small amount of water in the alcohol and to limitations of the infrared light detector. The present note records the remeasured spectrum and its temperature dependence. The value of the energy at the absorption maximum (EAmax) is 155 zJ (0.97 eV) at 299 K and 112 zJ (0.70 eV) at 338 K; the corresponding values of G epsilon max (10-22 m2 aJ-1) are 1.06 and 0.74. These unusually large changes are attributed to the abnormally rapid decrease of dielectric permittivity of tert-butanol with increasing temperature. The band asymmetry at 299 K is Wb/Wr = 1.8.Key words: optical absorption spectrum, solvated electron, solvent effects, tert-butanol, temperature dependence.

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