scholarly journals REGULAR ARTICLE Semi-Empirical and HOMO, LUMO Studies of Some Chlorinated Pesticides Compounds

2018 ◽  
Vol 6 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Mamoun S.M. Abd El-Kareem
Keyword(s):  
Chlorinated Pesticides ◽  
Semi Empirical ◽  
Homo Lumo

Semi-Empirical Study Of Rotenone Stemonone: HOMO, LUMO and Reactivity Descriptors

2019 ◽  
Vol 10 (4) ◽  
pp. 1332-1336 ◽  
Author(s):  
Francisco Nithael Melo Lucio ◽  
David Lopes Santiago de Oliveira ◽  
Emanuelle Machado Marinho ◽  
Carlos Lacerda de Morais Filho ◽  
Francisco Rogenio Silva Mendes ◽  
...  
Keyword(s):  
Empirical Study ◽  
Reactivity Descriptors ◽  
Semi Empirical ◽  
Homo Lumo

ELECTRONIC STRUCTURE OF THE FINITE-SIZED SINGLE-WALLED CARBON NANOTUBES

2003 ◽  
Vol 02 (03) ◽  
pp. 141-152 ◽  
Author(s):  
ANURAK UDOMVECH ◽  
TEERAKIAT KERDCHAROEN ◽  
VUDHICHAI PARASUK ◽  
YUTHANA TANTIRUNGROTECHAI ◽  
TANAKORN OSOTCHAN
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Energy Gap ◽  
Single Walled Carbon Nanotubes ◽  
Scanning Tunneling ◽  
Lumo Energy ◽  
Single Walled Carbon ◽  
Semi Empirical ◽  
Walled Carbon Nanotubes ◽  
Homo Lumo

The effects of tubule length and terminal capping on the geometrical and electronic properties of finite-sized zig-zag (9, 0) single-walled carbon nanotubes (SWNT), which length varying from 2 up to 12 unit cells (~50 Å), were investigated using molecular mechanics, semi-empirical methods (AM1 and EHMO) and density functional theory (B3LYP). AM1 method indicates how the nanotube ends are capped affects strongly the tubule geometric parameters. Although these effects seem to decrease exponentially as the tube gets longer, the converging values for C–C bond length in the open- and closed-end structures are slightly different. It was learned that combination of low-level methods like AM1 and EHMO (which tend to overestimate and underestimate the HOMO–LUMO energy gap, respectively) together with high-level method such as DFT is efficient to estimate band gap for finite-sized nanostructures. The HOMO–LUMO energy gaps obtained from semi-empirical and DFT methods decrease as the tubule length increases. Terminal capping also affects strongly the electronic structure of finite-sized nanotube. Thus, closing the terminal ends by fullerene hemisphere broadens the energy gap of the hydrogen-saturated open-end nanotube. Although the open-end SWNT has much lower AM1 HOMO–LUMO energy gap than the closed-end SWNT, these orbitals unfortunately are localized near the capping hydrogen, thereby do not provide conducting channels for electrons. By comparing only the delocalized frontier orbitals, both structures yield closer energy gap. Analysis of the energy gap based on EHMO, AM1 and DFT results suggests that both open- and closed-end finite-sized SWNT are semiconductor, in agreement with recent scanning tunneling experiment. It was found that the slight accumulated negative charges are likely to locate at the nanotube's fullerene tips.

scholarly journals SEMI-EMPIRICAL AND DFT STUDIES OF MIXED-LIGAND COMPLEXES OF CU(II) DIMETHYLGLYOXIM

2014 ◽  
Vol 22 (22) ◽  
pp. 36-46
Author(s):  
I. A. ADEJORO ◽  
B. AKINTOYE ◽  
O. O. ADEBOYE
Keyword(s):  
Bond Angle ◽  
Theoretical Calculations ◽  
Dipole Moments ◽  
Calculated Data ◽  
Mixed Ligand ◽  
Band Gaps ◽  
Mixed Ligand Complexes ◽  
Semi Empirical ◽  
Homo Lumo ◽  
Good Agreement

The non-electrolyte mixed-ligand complexes of the general formula [M(Hdmg)B], M=Cu(II), Hdmg=dimethylgloximato monoanion, B=2-arninophenol(2-aph), diethylamine (dea), or malonic acid (MOH) has been synthesized and characterized. However theoretical calculations were carried out to obtained the geometric properties such as bond length, bond angle, and dihedrals. Thermodynamic parameters, vibrational and electronic properties, dipole moments, and HOMO-LUMO band gaps of the complex with different substituents were also calculated. These properties were obtained using the PM3 and DFT with B3LYP at 6-31G* level. Comparisons were made and it was observed that the calculated data are in good agreement with experimental data.

Semi-empirical evaluation of Sr-Ar difference potentials

1986 ◽  
Vol 47 (7) ◽  
pp. 1149-1154
Author(s):  
Le Quang Rang ◽  
D. Voslamber
Keyword(s):  
Empirical Evaluation ◽  
Difference Potentials ◽  
Semi Empirical
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