Density Functional Study on the Configurations of Nen (n=2~36) Clusters

2017 ◽  
Vol 727 ◽  
pp. 381-387
Author(s):  
Chang Ning Peng ◽  
Xing Rong Zheng
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Functional Study ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Quantum Chemistry Calculations ◽  
Average Bond

Based on the First-principles and the method of quantum chemistry calculations, using the B3LYP method and 6-31G basis set of the density functional theory (DFT), the configurations and binding energy of Nen (n=2~36) clusters are calculated and studied theoretically after the calculation of geometry optimization. By changing the atomic number n of the Nen (n=2~36) clusters, it obtained that the stable structures, the binding energy and HOMO - LUMO energy gap of the Nen (n=2~36) clusters under the same ideal conditions, and summarizes the change rule of the stable configurations, the binding energy and the average bond length of the Nen (n=2~36) clusters.

scholarly journals Structure, MESP and HOMO-LUMO study of 10-Acetyl- 10H-phenothiazine 5-oxide using vibrational spectroscopy and quantum chemical methods

BIBECHANA ◽  
2012 ◽  
Vol 9 ◽  
pp. 38-49
Author(s):  
Bhawani Datt Joshi ◽  
Poonam Tandon ◽  
Sudha Jain
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Geometry Optimization ◽  
Basis Set ◽  
Orbital Energy ◽  
Potential Energy Distribution ◽  
Hartree Fock ◽  
Quantum Chemical Methods ◽  
B3lyp Method

In this communication, we have presented the geometry optimization, complete vibrational study with potential energy distribution (PED) and frontier orbital energy gap for the 10-Acetyl-10H-phenothiazine 5-oxide (APTZ) molecule using ab initio Hartree-Fock (HF) and density functional theory (DFT/B3LYP) method employing 6-311++G(d,p) basis set. The calculated IR and Raman spectra with their intensities, molecular electrostatic potential (MESP) surface and highest occupied molecular orbital (HOMO) - lowest unoccupied molecular orbital (LUMO) plot have been given. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7151 BIBECHANA 9 (2013) 38-49

DFT Studies and Quantum Chemical Calculations of Benzoyl Thiourea Derivatives Linked with Morpholine and Piperidine for the Evaluation of Antifungal Activity

2022 ◽  
Vol 12 ◽  
Author(s):  
Rameshwar K. Dongare ◽  
Shaukatali N. Inamdar ◽  
Radhakrishnan M. Tigote
Keyword(s):  
Antifungal Activity ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Basis Set ◽  
Functional Study ◽  
Chemical Parameters ◽  
Thiourea Derivatives ◽  
Quantum Chemical Parameters ◽  
B3lyp Method

Herein, we report the density functional study of benzoyl thiourea derivatives linked to morpholine and piperidine to evaluate their antifungal activity. Overall six compounds BTP 1-3 and BTM 4-6 were optimized with DFT using the B3LYP method with 6-31G(d,p) basis set. The molecular geometry, bond lengths, bond angles, atomic charges and HOMO-LUMO energy gap have been investigated. The structural parameters have been compared with the reported experimental results and structure- antifungal activity relationship is explored in details. The calculated results from DFT were discussed using all Quantum chemical parameters of the compounds. Introduction: Benzoyl thiourea derivatives linked with morpholine and piperidine were reported to have good antifungal activity. Objective: To find the correlations between the quantum chemical calculations and the antifungal activity for the benzoyl thiourea derivatives linked with morpholine and piperidine. Method: Optimization was carried out with DFT using B3LYP method utilizing 6-31G(d,p) basis set. Results: A good correlation between the quantum chemical calculations and the antifungal activity for the benzoyl thiourea derivatives linked with morpholine and piperidine was found. Conclusion: The DFT study of benzoyl thiourea derivatives linked to morpholine and piperidine was evaluated for their antifungal activity and it showed good correlations of activity with the quantum chemical parameters.

scholarly journals Noble gas cluster ions

2018 ◽  
Vol 174 ◽  
pp. 06003
Author(s):  
Yunus Kaya ◽  
Yalçin Kalkan ◽  
Rob Veenhof
Keyword(s):  
Density Functional ◽  
Noble Gas ◽  
Kinetic Studies ◽  
Basis Set ◽  
Cluster Ions ◽  
Functional Theory ◽  
B3lyp Method ◽  
Xenon Cluster ◽  
The Density Functional Theory ◽  
Potential Basis

In this work, a reaction mechanism of formation of noble gas (Ng) cluster ions has been theoretically investigated in detail. The kinetic studies of formation of Xe+Xe cluster in Xe, Ar+Ar cluster ions in Ar, and Ne+Ne cluster ions in Ne have been made as theoretically. The optimized structures in the ground state were calculated using the density functional theory (DFT) by the B3LYP method combined with the Stuttgart/Dresden effective core potential basis set (SDD). In addition, we calculated the rate constants of all cluster formations. The results are 1.15 × 10−31, 3.58 × 10−31, 0.23 × 10−31cm6/s, respectively for Neon, Argon, Xenon cluster ions.

Investigation on the photodriven catalytic coupling reaction mechanism of p-aminothiophenol on the silver cluster

2015 ◽  
Vol 14 (03) ◽  
pp. 1550019 ◽  
Author(s):  
Lai-Cai Li ◽  
Wei Wang ◽  
Dan Peng ◽  
Rui Pan ◽  
An-Min Tian
Keyword(s):  
Reaction Mechanism ◽  
Density Functional ◽  
Transition States ◽  
Coupling Reaction ◽  
Silver Cluster ◽  
Basis Set ◽  
Functional Theory ◽  
Orbital Interactions ◽  
B3lyp Method ◽  
The Density Functional Theory

The catalytic coupling reaction mechanism for the transformation from p-aminothiophenol (PATP) to 4,4′-dimercaptoazobenzene (4,4′-DMAB) on silver cluster was studied by the density functional theory. All the reactants, intermediates, transition states and products were optimized with B3LYP method at 6-311+G (d, p) basis set (the LanL2DZ basis set was used for Ag atom). Transition states and intermediates have been confirmed by the corresponding vibration analysis and intrinsic reactions coordinate (IRC). In addition, nature bond orbital (NBO) and atoms in molecules (AIM) theories have been used to analyze orbital interactions and bond natures. Consistent with the conclusions reported in the literature, the core of obtaining the production of azobenzene according to the coupling reaction of PATP absorbed on Ag 5 clusters is the elimination of two H atoms. Meanwhile, we find that the effect of illumination in that reaction matters a lot. We also found in PATP molecular that the synergistic catalytic effect of S end absorbed on the catalyzer draws dramatically evident under no illumination conditions, while it draws less obvious under light. According to the paper's conclusion, PATP absorbed on the surface of Ag 5 tends to generate azobenzene easily.

scholarly journals On the Use of DFT+U to Describe the Electronic Structure of TiO2 Nanoparticles: (TiO2)35 as a Case Study

2020 ◽  
Author(s):  
Angel Morales ◽  
Stephen Rhatigan ◽  
Michael Nolan ◽  
Frances Illas
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Plane Waves ◽  
Basis Set ◽  
Basis Sets ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Rotationally Invariant

One of the main drawbacks in the density functional theory (DFT) formalism is the underestimation of the energy gaps in semiconducting materials. The combination of DFT with an explicit treatment of electronic correlation with a Hubbard-like model, known as DFT+<i>U</i> method, has been extensively applied to open up the energy gap in materials. Here, we introduce a systematic study where the selection of <i>U</i> parameter is analyzed considering two different basis sets: plane-waves (PWs) and numerical atomic orbitals (NAOs), together with different implementations for including <i>U</i>, to investigate the structural and electronic properties of a well-defined bipyramidal (TiO<sub>2</sub>)<sub>35 </sub>nanoparticle (NP). This study reveals, as expected, that a certain <i>U</i> value can reproduce the experimental value for the energy gap. However, there is a high dependence on the choice of basis set and, and on the +<i>U</i> parameter employed. The present study shows that the linear combination of the NAO basis functions, as implemented in FHI-aims, requires a lower <i>U</i> value than the simplified rotationally invariant approaches as implemented in VASP. Therefore, the transferability of <i>U</i> values between codes is unfeasible and not recommended, demanding initial benchmark studies for the property of interest as a reference to determine the appropriate value of <i>U</i>.

scholarly journals Crystal structure, solvothermal synthesis, thermogravimetric studies and DFT calculations of a five-coordinate cobalt(II) compound based on theN,N-bis(2-hydroxyethyl)glycine anion

2016 ◽  
Vol 72 (10) ◽  
pp. 1463-1467 ◽  
Author(s):  
Yanling Zhou ◽  
Xianrong Liu ◽  
Qijun Wang ◽  
Lisheng Wang ◽  
Baoling Song
Keyword(s):  
Molecular Structure ◽  
Density Functional ◽  
Ethanol Solution ◽  
Basis Set ◽  
Functional Theory ◽  
Trigonal Bipyramidal ◽  
Dimensional Network ◽  
B3lyp Method ◽  
The Density Functional Theory ◽  
Cl Atoms

The reaction of CoCl2·6H2O,N,N-bis(2-hydroxyethyl)glycine and triethylamine (Et3N) in ethanol solution under solvothermal conditions produced crystals of [N,N-bis(2-hydroxyethyl)glycinato]chloridocobalt(II), [Co(C6H12NO4)Cl]. The CoIIion is coordinated in a slightly distorted trigonal–bipyramidal environment which is defined by three O atoms occupying the equatorial plane and the N and Cl atoms in the apical sites. In the crystal, two types of O—H...O hydrogen bonds connect the molecules, forming a two-dimensional network parallel to (001). The molecular structure of the title compound confirms the findings of FTIR, elemental analysis, ESI–MS analysis and TG analysis. By using the density functional theory (DFT) (B3LYP) method with 6-31G(d) basis set, the molecular structure has been calculated and optimized.

scholarly journals Theoretical investigation of the Anti-Parkinson drug rasagiline and its salts: conformations and infrared spectra

2012 ◽  
Vol 10 (2) ◽  
pp. 395-406 ◽  
Author(s):  
U. Başköse ◽  
Sevgi Bayarı ◽  
Semran Sağlam ◽  
Hacı Özışık
Keyword(s):  
Density Functional ◽  
Single Point ◽  
Normal Modes ◽  
Basis Set ◽  
Stable Conformer ◽  
Functional Theory ◽  
Point Energy ◽  
Vibrational Assignments ◽  
B3lyp Method ◽  
The Density Functional Theory

AbstractThe conformational analysis of rasagiline [N-propargyl-1(R)-aminoindan] was performed by the density functional theory (DFT) B3LYP method using the 6–31++G (d,p) basis set. A single point energy calculations based on the B3LYP optimized geometries were also performed at MP2/6-31++G (d, p) level. The vibrational frequencies of the most stable conformer of rasagiline was calculated at the B3LYP level and vibrational assignments were made for normal modes on the basis of scaled quantum mechanical force field (SQM) method. The influence of mesylate and ethanedisulfonate salts on the geometry of rasagiline free base and its normal modes are also discussed.

scholarly journals Synthesis, characterization, DFT, and TD-DFT studies of (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite)

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Hitler Louis ◽  
Obieze C. Enudi ◽  
Joseph O. Odey ◽  
Izubundu B. Onyebuenyi ◽  
Azuaga T. Igbalagh ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Nbo Analysis ◽  
Basis Set ◽  
Orbital Interactions ◽  
B3lyp Method ◽  
Td Dft ◽  
Donor Acceptor ◽  
Molecular Orbital Analysis

AbstractIn this study, (E)-5-((4,6-dichloro-1,3,5-triazin-2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2,7-diylbis(hydrogen sulfite), a cyanurated H-acid (CHA) azo dye, was synthesized and characterized using FT-IR spectrophotometer and GC-MS spectroscopy. A density functional theory (DFT) based B3LYP and CAM-B3LYP method with 6–311 + G (d,p) basis set analysis was computed for HOMO-LUMO, natural bonding orbitals (NBO), UV-Vis absorptions and excitation interactions, in order to understand its molecular orbital excitation properties. A low Energy gap (Eg) of 2.947 eV was obtained from the molecular orbital analysis, which showed that HOMO to LUMO transition is highly feasible; hence CHA is adequate for diverse electronic and optic applications. Studies of the first five excitations (S0 → S1/S2/S3/S4/S5) of CHA revealed that S0 → S1 and S0 → S3 are π → π* type local excitations distributed around the –N=N– group; S0 → S2, a Rydberg type local excitation; S0 → S4, a highly localized π → π* excitation; while S0 → S5 is an n → π* charge transfer from a benzene ring to –N=N– group. From NBO analysis, we obtained the various donor–acceptor orbital interactions contributing to the stabilization of the studied compound. Most significantly, some strong hyper-conjugations (n → n*) within fragments, and non-bondingand anti-bonding intermolecular (n → n*/π* and π → n*/π*) interactions were observed to contribute appreciable energies. This study is valuable for understanding the molecular properties of the azo dyes compounds and for synthesizing new ones in the future.

scholarly journals On the Use of DFT+U to Describe the Electronic Structure of TiO2 Nanoparticles: (TiO2)35 as a Case Study

2020 ◽  
Author(s):  
Angel Morales ◽  
Stephen Rhatigan ◽  
Michael Nolan ◽  
Frances Illas
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Plane Waves ◽  
Basis Set ◽  
Basis Sets ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structural And Electronic Properties ◽  
Rotationally Invariant

One of the main drawbacks in the density functional theory (DFT) formalism is the underestimation of the energy gaps in semiconducting materials. The combination of DFT with an explicit treatment of electronic correlation with a Hubbard-like model, known as DFT+<i>U</i> method, has been extensively applied to open up the energy gap in materials. Here, we introduce a systematic study where the selection of <i>U</i> parameter is analyzed considering two different basis sets: plane-waves (PWs) and numerical atomic orbitals (NAOs), together with different implementations for including <i>U</i>, to investigate the structural and electronic properties of a well-defined bipyramidal (TiO<sub>2</sub>)<sub>35 </sub>nanoparticle (NP). This study reveals, as expected, that a certain <i>U</i> value can reproduce the experimental value for the energy gap. However, there is a high dependence on the choice of basis set and, and on the +<i>U</i> parameter employed. The present study shows that the linear combination of the NAO basis functions, as implemented in FHI-aims, requires a lower <i>U</i> value than the simplified rotationally invariant approaches as implemented in VASP. Therefore, the transferability of <i>U</i> values between codes is unfeasible and not recommended, demanding initial benchmark studies for the property of interest as a reference to determine the appropriate value of <i>U</i>.

Efficient Synthesis, Spectroscopic and Quantum Chemical Study of 2,3-Dihydrobenzofuran Labelled Two Novel Arylidene Indanones: A Comparative Theoretical Exploration

2020 ◽  
Vol 17 (2) ◽  
pp. 146-161
Author(s):  
Rahul Ashok Shinde ◽  
Vishnu Ashok Adole ◽  
Bapu Sonu Jagdale ◽  
Thansing Bhavsing Pawar ◽  
Bhatu Shivaji Desale
Keyword(s):  
Magnetic Resonance ◽  
Density Functional ◽  
Computational Study ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Reactivity Descriptors ◽  
B3lyp Method ◽  
The Density Functional Theory

Indanone and 2,3-dihydrobenzofuran scaffolds are considered as special structures in therapeutic science and explicitly associated with various biologically potent compounds. In the present disclosure, we report the synthesis of two new 2,3-dihydrobenzofuran tethered arylidene indanones via an environmentally adequate and viable protocol. The two compounds revealed in this have been characterized well by analytical methods; proton magnetic resonance (PMR), carbon magnetic resonance (CMR). The Density Functional Theory (DFT) study has been presented for the spectroscopic, structural and quantum correlation between (E)-2-((2,3-dihydrobenzofuran-5-yl)methylene)-2,3-dihydro-1H-inden-1-one (DBDI) and (E)-7-((2,3-dihydrobenzofuran-5-yl)methylene)-1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one (DBTI). Optimized geometry, frontier molecular orbital, global reactivity descriptors, and thermodynamic parameters have been computed for DBDI and DBTI. DFT/B3LYP method using basis set 6-311++G (d,p) has been employed for the computational study. Mulliken atomic charges are established by using 6-311G (d,p) basis set. Besides, molecular electrostatic potential for DBDI and DBTI is also explored to locate the electrophilic and nucleophilic centres.

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