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

scholarly journals Ab InitioDensity Functional Theory Investigation of the Interaction between Carbon Nanotubes and Water Molecules during Water Desalination Process

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Loay A. Elalfy ◽  
Walid M. I. Hassan ◽  
Wael N. Akl
Keyword(s):  
Carbon Nanotubes ◽  
Reverse Osmosis ◽  
Molecular Orbital ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Water Desalination ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Dynamics Simulations

Density functional theory calculations using B3LYP/3-21G level of theory have been implemented on 6 carbon nanotubes (CNTs) structures (3 zigzag and 3 armchair CNTs) to study the energetics of the reverse osmosis during water desalination process. Calculations of the band gap, interaction energy, highest occupied molecular orbital, lowest unoccupied molecular orbital, electronegativity, hardness, and pressure of the system are discussed. The calculations showed that the water molecule that exists inside the CNT is about 2-3 Å away from its wall. The calculations have proven that the zigzag CNTs are more efficient for reverse osmosis water desalination process than armchair CNTs as the reverse osmosis process requires pressure of approximately 200 MPa for armchair CNTs, which is consistent with the values used in molecular dynamics simulations, while that needed when using zigzag CNTs was in the order of 60 MPa.

Cross-conjugation as a Motif for Organic Non-Linear Optical Molecules

2014 ◽  
Vol 1698 ◽  
Author(s):  
Meghana Rawal ◽  
Kerry Garrett ◽  
Andreas F. Tillack ◽  
Werner Kaminsky ◽  
Evgheni Jucov ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Dipole Moments ◽  
X Ray Diffraction ◽  
Conjugated Molecules ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Donor And Acceptor ◽  
Vis Spectroscopy ◽  
Lowest Unoccupied Molecular Orbital

ABSTRACTWe studied the effect of a cross-conjugated bridging group (χC) on charge-transfer in a push-pull chromophore system. The hyperpolarizability of such molecules was found to be comparable to that of a fully π-conjugated molecule (πC) with the same donor and acceptor. The cross-conjugated moiety was then applied as a pendant to a fully π-conjugated chromophore containing a tricyanopyrroline acceptor (TCP). The addition of a χC moiety did not alter the intrinsic hyperpolarizability and provides an avenue for extending and aiding πC systems. The molecules were examined by X-ray diffraction (XRD), hyper-Raleigh scattering (HRS) and UV-visible (UV-vis) spectroscopy. Experimental results were compared with the predictions of density functional theory (DFT). Cross-conjugated molecules have comparable β values, relative to πC molecules, due to reduced spatial overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Thus, the χC architecture could facilitate independent modification of donor and acceptor strengths while minimizing unfavorable effects on electronic transitions and dipole moments.

AB INITIO AND DFT THEORETICAL INVESTIGATIONS ON NOVEL PORPHYRIN–FULLERENE SUPRAMOLECULAR DYADS FOR PHOTOVOLTAIC DEVICES

2008 ◽  
Vol 07 (05) ◽  
pp. 1055-1069 ◽  
Author(s):  
TAPAS MANNA ◽  
SUMANTA BHATTACHARYA
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Density Functional ◽  
Conformational Stability ◽  
Density Functional Theory Calculations ◽  
Orbital State ◽  
Highest Occupied Molecular Orbital ◽  
Theoretical Investigations ◽  
Lowest Unoccupied Molecular Orbital ◽  
Porphyrin Moiety

The conformational stability and electronic structures of novel H 2-(1) and Zn-tetraphenylporphyrin–[60]fullerene (2) dyads, in which the [60]fullerene is directly linked to the tetrapyrrolic rings by ethynylenephenylene subunits, have been studied by ab initio and density functional theory calculations. From the investigation on frontier molecular orbitals, it was found that the lowest unoccupied molecular orbital state of these supramolecules is localized on the fullerene and that the highest occupied molecular orbital state is localized on the porphyrin moiety. Molecular electrostatic potential maps clearly demonstrate the electron transfer phenomena from the porphyrin moiety to the fullerene in dyads 1 and 2.

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 Relationship between the Electrical Characteristics of Molecules and Fast Streamers in Ester Insulation Oil

2020 ◽  
Vol 21 (3) ◽  
pp. 974 ◽  
Author(s):  
Kaizheng Wang ◽  
Feipeng Wang ◽  
Ziyi Lou ◽  
Qiuhuang Han ◽  
Qi Zhao ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Ester Group ◽  
Electrical Characteristics ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lightning Impulse ◽  
Lowest Unoccupied Molecular Orbital ◽  
Natural Ester ◽  
Insulation Oil

The effects of C=C, ester and β-H groups on the ionization potential (IP) and electron affinity (EA) of molecules in natural ester insulation oil were investigated by density functional theory (DFT). The major contribution to the highest occupied molecular orbital (HOMO) comes from the carbon atoms adjacent to C=C. Thus, the IPs of triglycerides decrease as the number of C=C double bonds increases. The C=C in alkanes may also lower the IP. However, the β-H in triglycerides has little effect on the IP, and C=C and β-H have only a small effect on the EAs of the triglycerides because of the major contributions of atoms near the ester group in triglycerides to the lowest unoccupied molecular orbital (LUMO). This study calculated the IPs of 53 kinds of molecules in FR3, which are significantly lower compared with those of molecules in mineral oil (MO) and trimethylolpropane triester without C=C. However, the lightning impulse breakdown voltage (LI Vb) of trimethylolpropane triester is still significantly lower than that of MO at the large gap. Therefore, the transition from slow to fast streamers under low lighting impulse voltage is determined by the ester group rather than by C=C and β-H. The ester group may attract more electrons, impacting itself more compared to alkane in MO and facilitating the transition from slow to fast streamers.

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.

Theoretical studies on lindqvist polyoxometalates [M6O19]n−(M = Mo, W, n=2; M = V, Nb, Ta, n=8) and derivatives: Electronic structures, stability and bonding

2017 ◽  
Vol 16 (06) ◽  
pp. 1750054 ◽  
Author(s):  
Xiao-Fang Su ◽  
Bo Zhu ◽  
Cai-Xia Wu ◽  
Li-Kai Yan ◽  
Zhong-Min Su
Keyword(s):  
Charge Density ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Density Functional ◽  
Geometrical Structure ◽  
Energy Gap ◽  
Lumo Energy ◽  
Functional Theory ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The geometrical and electronic structures of [M6O[Formula: see text]][Formula: see text] (M [Formula: see text] Mo, W, [Formula: see text]; M [Formula: see text] V, Nb, Ta, [Formula: see text]) and their derivatives were investigated by using density functional theory methods. The results indicate that the geometrical structure of [V6O[Formula: see text]][Formula: see text] is not different from other Lindqvist-type anions. The energy gap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) (HOMO[Formula: see text]LUMO energy gap) of [V6O[Formula: see text]][Formula: see text] is smaller than those of same charge anions, [Nb6O[Formula: see text]][Formula: see text] and [Ta6O[Formula: see text]][Formula: see text]. In addition, the charge density [Formula: see text] of [V6O[Formula: see text]][Formula: see text] is larger when compared with those of other studied clusters. The investigation on the derivatives shows that the valence of V atom (V[Formula: see text] or V[Formula: see text]) and the methoxy ligand influence the HOMO[Formula: see text]LUMO energy gap and the charge density [Formula: see text] of the studied clusters.

DFTB Calculation of Si Atomic Chains’ Structures and Electronic Properties

2016 ◽  
Vol 848 ◽  
pp. 494-497
Author(s):  
Xiu Min Xu ◽  
Li Jun Wu ◽  
Lin Zhang
Keyword(s):  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Tight Binding ◽  
Functional Theory ◽  
Symmetrical Distribution ◽  
Highest Occupied Molecular Orbital ◽  
Atomic Chains ◽  
Lowest Unoccupied Molecular Orbital

In this paper, structures and electronic properties of atomic chains with 5 to 20 silicon atoms and different atomic distances (d = 1.652 ~ 2.752Å) were calculated by the tight-binding method based on density functional theory. The results showed that the majority of the silicon atomic chains were symmetrical structures. When the number of silicon atoms was small, the silicon atomic chains were linear, when the silicon atomic chains had seven or more silicon atoms zigzag structures appeared. With the increase of the distance between atoms, atomic chains were gathering. When the number of silicon atoms was between 10 and 20, the charges on the silicon atoms appeared as a symmetrical distribution. With the increase of the number of atoms, the energy of silicon atomic chains decreased gradually. As the distance between atoms and atomic number changed, HOMO (highest occupied molecular orbital electrons) -LUMO (lowest unoccupied molecular orbital electrons) energy gap changed as well.

scholarly journals Synthesis, spectroscopic characterization and computational studies of Schiff base complexes of tin(IV) chloride

2019 ◽  
Vol 42 (1) ◽  
pp. 28-36
Author(s):  
Nitesh Jaiswal ◽  
Ajeet Kumar Kushwaha ◽  
Avadhesh Pratap Singh ◽  
Raj Kumar Dubey
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Molecular Geometry ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Schiff Base Complexes ◽  
Molar Ratios ◽  
Highest Occupied Molecular Orbital ◽  
Computational Calculations ◽  
Lowest Unoccupied Molecular Orbital

Abstract Reaction of anhydrous tin(IV) chloride with mono functional bidentate Schiff bases (sbnH), in 1:2 molar ratios, gives complexes of the type, [(sbn)2SnCl2] (1-4) (where, n=1-4; sb=2-(((4-chlorophenyl)imino)methyl)phenol, sb1H, I; 2-(((4-bromophenyl)imino)methyl) phenol, sb2H, II; 2-(((4-chlorophenyl)imino)methyl)-6-methoxyphenol, sb3H, III and 2-(((4-bromo phenyl)imino)methyl)-6-methoxyphenol, sb4H, IV. All the tin(IV) complexes (1-4) were colored solid and soluble in organic solvents. The synthesized complexes were characterized by elemental analysis (C, H, N and Sn), IR, UV-Vis, NMR (1H, 13C and 119Sn) spectroscopy and mass spectrometry. On the basis of spectroscopic studies, six coordination around tin atom has been proposed tentatively. The computational calculations using density functional theory (DFT) of ligands and complexes were also performed to obtained optimized molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and other parameter.

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