scholarly journals ZnO Nanocrystal-Based Chloroform Detection: Density Functional Theory (DFT) Study

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 769 ◽  
Author(s):  
H. Y. Ammar ◽  
H. M. Badran ◽  
Ahmad Umar ◽  
H. Fouad ◽  
Othman Y. Alothman
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Sensing Applications ◽  
Specific Geometry ◽  
Lowest Unoccupied Molecular Orbital ◽  
Zno Nanoclusters ◽  
Energy Frontier

We investigated the detection of chloroform (CHCl3) using ZnO nanoclusters via density functional theory calculations. The effects of various concentrations of CHCl3, as well as the deposition of O atoms, on the adsorption over ZnO nanoclusters were analyzed via geometric optimizations. The calculated difference between the highest occupied molecular orbital and the lowest unoccupied molecular orbital for ZnO was 4.02 eV. The most stable adsorption characteristics were investigated with respect to the adsorption energy, frontier orbitals, elemental positions, and charge transfer. The results revealed that ZnO nanoclusters with a specific geometry and composition are promising candidates for chloroform-sensing applications.

scholarly journals Density Functional Theory Study of CL-20/Nitroimidazoles Energetic Cocrystal Compounds in an External Electric Field

2021 ◽  
Author(s):  
xiaosong Xu ◽  
Renfa Zhang ◽  
Wenxin Xia ◽  
Peng Ma ◽  
Congming Ma ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electric Field ◽  
Nitro Group ◽  
External Electric Field ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

Abstract The external electric field has a significant influence on the sensitivity of the energetic cocrystal materials. In order to find out the relationship between the external electric field and sensitivity of energetic cocrystal compounds 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/1,4-dinitroimidazole (CL-20/1,4-DNI), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/1-methyl-2,4-dinitro-1H-imidazole (CL-20/2,4-MDNI) and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/1-methyl-4,5-dinitro-1H-imidazole (CL-20/4,5-MDNI). In this work, density functional theory (DFT) at B3LYP-D3/6-311+G(d,p) and M062X-D3/ma-def2 TZVPP levels was employed to calculate the bond dissociation energies (BDEs) of selected N-NO2 trigger bonds, frontier molecular orbitals, electrostatic potentials (ESPs) and nitro group charges (QNO2) under different external electric field. The results show that as the positive electric field intensity increases, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy gap and BDEs become smaller, and the local positive ESPs becomes larger, so that the energetic cocrystals tends to have higher sensitivity. In addition, the linear fitting results show that the trigger bond length and nitro group charge changes are closely related to the external electric field strength.

scholarly journals Simulation Study of Structural and Electronic Properties for Adducts complexes of Bis(Acetylacetonato)oxoVandium (IV) with 4-(Para-substituted phenyl)-1,2,3-Selenadiazole

2021 ◽  
Vol 2063 (1) ◽  
pp. 012002
Author(s):  
Dalal H Alsawad ◽  
Ali A Al-Riyahee ◽  
Ali J Hameed
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Lowest Unoccupied Molecular Orbital ◽  
Reorganization Energies ◽  
Cis And Trans ◽  
Optimized Geometries

Abstract A series of 4-(para-substituted phenyl)-1,2,3-selenadiazole adducts of [VO(acac)2] were studied by density functional theory (DFT) calculations. The 4-(para-substituted phenyl)-1,2,3-selenadiazole molecules have been selected to be bound with vanadium atom in [VO(acac)2] through Se, N2 and N3. The resulting adducts have been investigated in two geometries (cis and trans) in order to show the effect of such structural change on the electronic properties of the studied adducts. The optimized geometries, (binding and reorganization) energies and the spatial distribution of the highest molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the adducts are presented and discussed.

scholarly journals Structure, Electronic And Vibrational Study of 7-Methyl-2,3-Dihydro-(1,3)Thiazolo(3,2-A) Pyrimidin-5-One by Using Density Functional Theory

2018 ◽  
Vol 22 (2) ◽  
pp. 1-11
Author(s):  
Bhawani Datt Joshi ◽  
Janga Bahadur Khadka ◽  
Atamram Bhatt
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Functional Theory ◽  
Hartree Fock ◽  
Solvent Phase ◽  
Lowest Unoccupied Molecular Orbital

 We have presented molecular structure and vibrational wavenumber assignments of 7-methyl-2,3-dihydro-(1,3)thiazolo(3,2-a)pyrimidin-5-one. Both ab initio Hartree-Fock and density functional theory employing 6-311++G(d,p) basis set have been used for the calculations. The scaled values of the calculated vibrational frequencies were used for assignments on the basis of potential energy distribution. The structure-activity relation has been interpreted by mapping molecular electrostatic potential surface. Electronic properties have been analyzed by using time dependent density functional theory (TD-DFT) for both gaseous and solvent phase. The calculated HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values show that the charge transfer occurs within the molecule. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, Page: 1-11 

Electronic and geometric structure of AuxCuy clusters studied by density functional theory

2014 ◽  
Vol 25 (06) ◽  
pp. 1450011 ◽  
Author(s):  
Y. Kadioglu ◽  
O. Üzengi Aktürk ◽  
M. Tomak
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Local Density ◽  
Three Dimensional ◽  
Binding Energies ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

We have determined the stable structures of Au Cu n, Au 2 Cu n, Au 3 Cu n and Au x Cu 8-x clusters. It has been observed that Au Cu n, Au 2 Cu n and Au 3 Cu n systems have two-dimensional (2D) structures up to six atoms and they become three-dimensional (3D) afterwards. Au x Cu 8-x clusters favor 3D structures till the Au 7 Cu 1 cluster. We have found a lowest energy isomer of Au 6 Cu 2 from the literature. Bond lengths, binding energies, density of states (DOS), highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) gaps, ionization potential (IP) and electron affinity (EA) have been calculated for these structures using the first principles density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA). Generally, we have observed the overlap between s electrons of Cu and p electrons of Au near the Fermi level. Charge transfers are calculated by using the Löwdin analysis. It is observed that one Cu atom does not significantly modify the clusters which have more gold atoms. It is also seen that these clusters generally have nonmagnetic properties and results are consistent with the hybridization between s and d orbitals of Au in Au x Cu 8-x clusters.

scholarly journals Spectroscopic Studies and Vibrational Assignments, Homo- Lumo, UV-VIS, NBO Analysis of Benzonitrile

2020 ◽  
Vol 13 (3) ◽  
pp. 225-239
Author(s):  
K. Rajalakshmi ◽  
S. Sharmila
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Studies ◽  
Nbo Analysis ◽  
Functional Theory ◽  
Vibrational Assignments ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
The Fourier Transform

The Fourier transform infrared and FT-Raman spectra of Benzonitrile have been recorded in region of 4000-400 and 4000-100 cm -1 respectively. A complete assignments and analysis of fundamental vibrational modes of the molecule have been carried out. The observed fundamental modes have been compared with harmonic vibrational frequencies computed using ab initio and density functional theory calculations by employing B3LYP functional at 6-311G(d, p) level and HF/6-311G(d, p).UV-Vis spectrum of the compound has been recorded, the natural bond orbital (NBO) electronic properties, such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been calculated with B3LYP/6-311G(d, p) level. These calculated energies show that charge transfer occurs within molecule. NBO analysis, thermodynamics properties and Mulliken charges of the title molecule are also calculated and interpreted

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