An ab initio cluster calculation of the photoemission spectrum and optical gap in La2CuO4

1990 ◽  
Vol 163 (1-3) ◽  
pp. 533-537 ◽  
Author(s):  
Richard L. Martin
Keyword(s):  
Ab Initio ◽  
Photoemission Spectrum ◽  
Cluster Calculation ◽  
Optical Gap

scholarly journals An ab initio effective solid-state photoluminescence by frequency constraint of cluster calculation

2020 ◽  
Vol 128 (23) ◽  
pp. 233102
Author(s):  
Akib Karim ◽  
Igor Lyskov ◽  
Salvy P. Russo ◽  
Alberto Peruzzo
Keyword(s):  
Solid State ◽  
Ab Initio ◽  
Cluster Calculation ◽  
Frequency Constraint

A First Model of Amorphous GaN from Ab Initio Molecular Dynamics

1996 ◽  
Vol 449 ◽  
Author(s):  
D. A. Drabold ◽  
Petra Stumm
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Ab Initio ◽  
Density Of States ◽  
Vibrational Spectra ◽  
Structural Model ◽  
Ab Initio Molecular Dynamics ◽  
Electronic Density ◽  
Optical Gap ◽  
Local Bonding

ABSTRACTA probable byproduct of growth of crystalline GaN is an amorphous phase of the material. In this paper, we propose a structural model of amorphous GaN obtained from ah initio molecular dynamics. The radial distribution function, local bonding, electronic density of states and vibrational spectra are described. The network we obtain is highly disordered but exhibits a large state-free optical gap, and has no wrong (homopolar) bonds. These predictions are intended to elucidate the experimental signatures of amorphous GaN.

scholarly journals Photoemission spectrum in paramagnetic FeO under pressure: Towards an ab initio description

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
S. Di Sabatino ◽  
J. Koskelo ◽  
J. A. Berger ◽  
P. Romaniello
Keyword(s):  
Ab Initio ◽  
Photoemission Spectrum

Size dependence of the optical gap of “small” silicon quantum dots: Ab initio and empirical correlation schemes

2013 ◽  
Vol 112 ◽  
pp. 231-234 ◽  
Author(s):  
Shanawer Niaz ◽  
Emmanuel N. Koukaras ◽  
Nikolaos P. Katsougrakis ◽  
Theodoros G. Kourelis ◽  
Dimitrios K. Kougias ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ab Initio ◽  
Size Dependence ◽  
Empirical Correlation ◽  
Silicon Quantum Dots ◽  
Optical Gap

Ab initio band theory approach to electron energy loss near edge structures

1988 ◽  
Vol 46 ◽  
pp. 506-507
Author(s):  
Xudong Weng ◽  
O.F. Sankey ◽  
Peter Rez
Keyword(s):  
Ab Initio ◽  
Local Density ◽  
Interpolation Method ◽  
Atomic Orbital ◽  
Plane Waves ◽  
Large Set ◽  
Theory Approach ◽  
Band Theory ◽  
Atomic Orbitals ◽  
Pseudopotential Calculations

Single electron band structure techniques have been applied successfully to the interpretation of the near edge structures of metals and other materials. Among various band theories, the linear combination of atomic orbital (LCAO) method is especially simple and interpretable. The commonly used empirical LCAO method is mainly an interpolation method, where the energies and wave functions of atomic orbitals are adjusted in order to fit experimental or more accurately determined electron states. To achieve better accuracy, the size of calculation has to be expanded, for example, to include excited states and more-distant-neighboring atoms. This tends to sacrifice the simplicity and interpretability of the method.In this paper. we adopt an ab initio scheme which incorporates the conceptual advantage of the LCAO method with the accuracy of ab initio pseudopotential calculations. The so called pscudo-atomic-orbitals (PAO's), computed from a free atom within the local-density approximation and the pseudopotential approximation, are used as the basis of expansion, replacing the usually very large set of plane waves in the conventional pseudopotential method. These PAO's however, do not consist of a rigorously complete set of orthonormal states.

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