Molecular and electronic structure of ozone and thiozone from LCAO local density calculations

1985 ◽  
Vol 63 (7) ◽  
pp. 1982-1987 ◽  
Author(s):  
Mario Morin ◽  
Aniko E. Foti ◽  
Dennis R. Salahub
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Local Minimum ◽  
Local Density ◽  
Molecular And Electronic Structure ◽  
Ground State Geometry ◽  
Good Agreement

LCAO local density calculations for ozone yield a ground state geometry in good agreement with experiment (R = 1.27 Å vs. 1.278 Å (exp.), θ = 117.5° vs. 116.8° (exp.)). A second local minimum is found about 45 kcal/mol higher for a cyclic geometry (R = 1.44 Å, θ = 60°). For S3 the calculations predict a bent ground state (R = 2.00 Å, θ = 116°) with the cyclic geometry (R = 2.125 Å, θ = 58°) about 15 kcal/mol higher.

ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF CRYSTALLINE C60

1992 ◽  
Vol 06 (06) ◽  
pp. 309-321 ◽  
Author(s):  
W.Y. CHING ◽  
MING-ZHU HUANG ◽  
YONG-NIAN XU ◽  
FANQI GAN
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Optical Spectrum ◽  
Local Density ◽  
Low Dielectric Constant ◽  
Experimental Measurements ◽  
Absorption Bands ◽  
Low Dielectric ◽  
Good Agreement

The electronic structure and optical properties of crystalline C 60 and their pressure dependence have been studied by first-principles local density calculations. It is shown that fcc C 60 has a low dielectric constant and an optical spectrum rich in structures. The spectrum shows five disconnected absorption bands in the 1.4 to 7.0 eV region with sharp structures in each band that can be attributed to critical point transitions. This is a manifestation of the localized molecular structure coupled with long range crystalline order unique to the C 60 crystal. At a sufficient high pressure, the structures in the optical spectrum start to merge due to the merging of the bands. These results are in good agreement with some recent experimental measurements.

Electronic Structure vs Phase in Al3V

1988 ◽  
Vol 141 ◽  
Author(s):  
J.-H. Xu
Keyword(s):  
Electronic Structure ◽  
Bulk Modulus ◽  
Total Energy ◽  
Crystal Structures ◽  
Lattice Constant ◽  
Density Of States ◽  
Phase Stability ◽  
Local Density ◽  
Young Modulus ◽  
Good Agreement

AbstractThe electronic structure of Al3V vs its two different crystal structures (DO22 and Ll2) were investigated using local density total energy approach. The calculated results of the total energy showed that in Al3V the tetragonal DO22 phase is energetically favored as compared to the cubic Ll2 phase, the total energy in the former case is about 60 mRy/F.U. lower than that in the later case. The calculated lattice constant (a=3.72 Å, c=8.20 Å) is in fairly good agreement with experiment (a=3.778 Å, c=8.326 Å),and the bulk modulus (1.3 Mbar) is comparable with the experimental Young modulus (150 GPa) for Al3Ti. Furthermore, it is interesting to note that the density of states at EF in the tetragonal DO22 phase (0.14 states/eV-F.U.) is about one order magnitude smaller than that in the Ll2 phase (2.89 states/eV-F.U.). The electronic structure of Al3V seems to be fairly satisfactory in explaining its phase stability.

EVALUATION OF LINEAR AND NONLINEAR MICROSCOPIC POLARIZABILITIES OF C60

1992 ◽  
Vol 06 (23n24) ◽  
pp. 3893-3901 ◽  
Author(s):  
Erik Westin ◽  
Arne Rosén
Keyword(s):  
Electronic Structure ◽  
Local Field ◽  
Ground State ◽  
Reasonable Agreement ◽  
Local Density ◽  
Density Approximation ◽  
Matrix Elements ◽  
Yield Values ◽  
Linear And Nonlinear ◽  
Centrosymmetric Molecule

The electronic structure of C 60 and some of its doped compounds have earlier been investigated at the level of the local density approximation, LDA, using a numerical LCAO approach. In this study, single particle wavefunctions determined from ground state LDA calculations are used for evaluation of dipole matrix elements which combined with a sum over state approach yield linear and nonlinear microscopic polarizabilities γ(1) and γ(3), respectively. Lorentz local field factors, as well as a simple RPA type correction are introduced to facilitate comparison with the dielectric function ε(ω) determined from films of C 60. γ(2) for a centrosymmetric molecule such as C 60 is zero and the lowest non-zero contribution to the polarizability is γ(3). Reasonable agreement is found with results from linear optical response experiments i.e. ellipsometric and EELS measurements on C 60 in solid or solution form. SHG, THG and DFWM experiments yield values close to the unscreened result, while invoking a RPA screening results in a non-resonant value about 2 orders of magnitude lower than most experiments.

scholarly journals Synthesis, molecular and electronic structure of an incomplete cuboidal Re3S4 cluster with an unusual quadruplet ground state

2012 ◽  
Vol 48 (21) ◽  
pp. 2713 ◽  
Author(s):  
Pavel A. Petrov ◽  
Alexander V. Virovets ◽  
Artem S. Bogomyakov ◽  
Rosa Llusar ◽  
Carlos J. Gómez-García ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Molecular And Electronic Structure

Protonation of 4 H-Pyran-4-one and its Sulfur Analogues. MNDO Study

1984 ◽  
Vol 39 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Mirjana Eckert-Maksić
Keyword(s):  
Electronic Structure ◽  
Experimental Evidence ◽  
Electron Density ◽  
Structural Features ◽  
Electron Drift ◽  
Strong Polarization ◽  
Appreciable Increase ◽  
Cyclic Conjugation ◽  
Molecular And Electronic Structure ◽  
Good Agreement

AbstractThe molecular and electronic structure of 4H-pyran-4-one and its mono- and disubstituted sulfur analogues (1-4) are studied by the MNDO method. The salient structural features are qualitatively reproduced and the trend of changes of geometric parameters is in good agreement with experiment. The charge distributions exhibit strong polarization due to the large π-electron drift toward the exo-heteroatom. The protonated conjugated acids are considered too. It is found that exo-heteroatom protonation is favoured by 60-80 kcal/mol over the attachment of the proton to the intraring heteroatom. This is in accordance with experimental evidence. It is rationalized by the higher electron density centered on the exo-heteroatom and the appreciable increase in aromatic cyclic conjugation taking place upon the exo-protonation.

scholarly journals Electronic structure and optical properties of (BeTe)n/(ZnSe)m superlattices

2016 ◽  
Vol 34 (1) ◽  
pp. 115-125 ◽  
Author(s):  
M. Caid ◽  
H. Rached ◽  
D. Rached ◽  
R. Khenata ◽  
S. Bin Omran ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Electronic Structure ◽  
Ground State ◽  
Optical Constants ◽  
Local Density ◽  
Band Gaps ◽  
Full Potential ◽  
Density Approximation ◽  
Binary Compounds

AbstractThe structural, electronic and optical properties of (BeTe)n/(ZnSe)m superlattices have been computationally evaluated for different configurations with m = n and m≠n using the full-potential linear muffin-tin method. The exchange and correlation potentials are treated by the local density approximation (LDA). The ground state properties of (BeTe)n/(ZnSe)m binary compounds are determined and compared with the available data. It is found that the superlattice band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(ω), the refractive index n(ω) and the refractivity R(ω), are calculated for radiation energies up to 35 eV.

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