Scaled quantum mechanical force fields for trifluoromethyl selenium derivatives. II. The (CF3)2Se and (CF3Se)2 molecules.

2009 ◽  
Vol 87 (3) ◽  
pp. 507-513 ◽  
Author(s):  
L. E. Fernández ◽  
E. L. Varetti
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Force Fields ◽  
Internal Force ◽  
Quantum Mechanical ◽  
Vibrational Properties ◽  
Functional Theory ◽  
Selenium Compounds ◽  
Definition Of ◽  
Theoretical Results

Force fields and vibrational properties of bis(trifluoromethyl)selenide, (CF3)2Se, and bis(trifluoromethyl)diselenide, (CF3Se)2, were calculated using density functional theory (DFT) techniques. The previously available experimental data and assignments for these molecules were confirmed by the theoretical results. These data were subsequently used in the definition of the corresponding scaled quantum mechanical (SQM) force fields. The obtained internal force constants are compared with results previously published for related selenium compounds.

scholarly journals A Quantum Chemistry Approach to the Force Fields of the Asymmetrical Thionyl Halides FS(O)Cl, CF3S(O)F and CF3S(O)Cl

2011 ◽  
Vol 66 (5) ◽  
pp. 499-504
Author(s):  
Angelina del C. Coronel ◽  
Myriam E. Gargiulo ◽  
Eduardo L. Varetti ◽  
Lis E. Fernández
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Quantum Mechanics ◽  
Density Functional ◽  
Force Fields ◽  
Internal Force ◽  
Vibrational Properties ◽  
Functional Theory ◽  
Definition Of ◽  
Theoretical Results

The vibrational properties of the asymmetrical thionyl halides FS(O)Cl, CF3S(O)F and CF3S(O)Cl were studied by means of density functional theory (DFT) techniques. The available experimental data and assignments for these molecules were compared with the theoretical results and revised. These data were subsequently used in the definition of the corresponding scaled quantum mechanics (SQM) force fields. A set of internal force constants was also calculated from such force fields

Scaled quantum mechanical force fields for trifluoromethyl selenium derivatives. I. The CF3SeCN and CF3SeCH3 molecules

2006 ◽  
Vol 84 (12) ◽  
pp. 1626-1631 ◽  
Author(s):  
L E Fernández ◽  
E L Varetti
Keyword(s):  
Density Functional ◽  
Force Fields ◽  
Chemical Species ◽  
Mechanical Force ◽  
Force Constants ◽  
Quantum Mechanical ◽  
Functional Theory ◽  
Definition Of ◽  
Theoretical Results ◽  
Mechanical Force Fields

Force fields and vibrational properties were calculated for the trifluoromethyl selenium derivatives, CF3SeCN and CF3SeCH3, by means of density functional theory (DFT) techniques. The existing experimental data and assignments for these molecules were confirmed by the theoretical results. These data were subsequently used in the definition of scaled quantum mechanical force fields for such chemical species. The obtained force constants are compared with results previously published for similar compounds.Key words: trifluoromethyl selenium, force constants, structure, DFT calculation.

scholarly journals A Quantum Chemistry Approach to the Force Fields of the Thionyl and Selenyl Halides, SOX2 and SeOX2

2007 ◽  
Vol 62 (12) ◽  
pp. 1491-1496
Author(s):  
Lis E. Fernández ◽  
Eduardo L. Varetti
Keyword(s):  
Experimental Data ◽  
Quantum Mechanics ◽  
Quantum Chemistry ◽  
Force Fields ◽  
Internal Force ◽  
Vibrational Frequencies ◽  
Force Constants ◽  
Definition Of ◽  
Theoretical Results

Force fields and vibrational frequencies were calculated for the molecules SOX2 and SeOX2, with X = F, Cl, Br, using DFT techniques. The previously available experimental data and assignments for the six molecules were confirmed by the theoretical results. These data were subsequently used in the definition of the corresponding scaled quantum mechanics (SQM) force fields. A comparison of the obtained internal force constants is made with results reported by other authors for the studied species.

Optical and Transport Effects in LaGa1-xMnxO3: Experiment and Modeling

2004 ◽  
Vol 834 ◽  
Author(s):  
N. Noginova ◽  
F. Chen ◽  
G. Chelule ◽  
V. I. Gavrilenko
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Energy Structure ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Optical Functions ◽  
Transport Effects ◽  
Electron Energy Structure ◽  
Theoretical Results

AbstractCharge transport and optical properties have been studied experimentally and theoretically in a series of LaGa1-xMnxO3 crystals in the dependence on the material composition. Electron energy structure and optical functions of LaGa1-xMnxO3 are calculated by ab initio pseudopotential method within density functional theory using generalized gradient approximation. Theoretical results are discussed in comparison with the experimental data for different alloy compositions.

A DFT study of thymine and its tautomers

2009 ◽  
Vol 87 (2) ◽  
pp. 406-415 ◽  
Author(s):  
Dongsheng Jiao ◽  
Hongyan Wang ◽  
Yanlan Zhang ◽  
Yu Tang
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Ionization Potential ◽  
Density Functional ◽  
The Other ◽  
Basis Sets ◽  
Electron Affinities ◽  
Proton Affinities ◽  
Functional Theory ◽  
Theoretical Results

The structures and the relative energies of six possible tautomers of the thymine base have been studied by density functional theory (DFT) using the B3LYP and BP86 functionals. The keto-thymine (T1) is predicted to be the most stable thymine tautomer, which is consistent with the other theoretical results and experimental data. The corresponding thymine cations and anions are studied using the same level of theory with double-ζ plus polarization and diffuse functions (DZP++) basis sets. The ionization potentials (IPs), the electron affinities (EAs), and proton affinities (PAs) for different protonation sites in thymine base are obtained. T1 has the largest ionization potential and the lowest proton affinity among all the considered thymine tautomers.

scholarly journals Theoretical study of the adsorption of benzene on coinage metals

2014 ◽  
Vol 10 ◽  
pp. 1775-1784 ◽  
Author(s):  
Werner Reckien ◽  
Melanie Eggers ◽  
Thomas Bredow
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Dispersion Correction ◽  
Functional Theory ◽  
Coinage Metals ◽  
Adsorption Energies ◽  
Theoretical Results ◽  
Good Agreement

The adsorption of benzene on the M(111), M(100) and M(110) surfaces of the coinage metals copper (M = Cu), silver (M = Ag) and gold (M = Au) is studied on the basis of density functional theory (DFT) calculations with an empirical dispersion correction (D3). Variants of the Perdew–Burke–Ernzerhof functionals (PBE, RPBE and RevPBE) in combination with different versions of the dispersion correction (D3 and D3(BJ)) are compared. PBE-D3, PBE-D3(BJ) and RPBE-D3 give similar results which exhibit a good agreement with experimental data. RevPBE-D3 and RevPBE-D3(BJ) tend to overestimate adsorption energies. The inclusion of three-center terms (PBE-D3(ABC)) leads to a slightly better agreement with the experiment in most cases. Vertical adsorbate–substrate distances are calculated and compared to previous theoretical results. The observed trends for the surfaces and metals are consistent with the calculated adsorption energies.

scholarly journals Ab initio и экспериментальное исследование электронных, оптических и колебательных свойств CdGa-=SUB=-2-=/SUB=-Te-=SUB=-4-=/SUB=-

2020 ◽  
Vol 62 (8) ◽  
pp. 1270
Author(s):  
З.А. Джахангирли ◽  
Т.Г. Керимова ◽  
И.А. Мамедова ◽  
С.А. Набиева ◽  
Н.А. Абдуллаев
Keyword(s):  
Experimental Data ◽  
Raman Scattering ◽  
Density Functional ◽  
Point Group ◽  
Group Symmetry ◽  
Vibrational Properties ◽  
Spectral Ellipsometry ◽  
Functional Theory ◽  
Semiconductor Compound ◽  
The Density Functional Theory

The electronic, optical, and lattice vibrational properties of CdGa2Te4 were studied experimentally using spectral ellipsometry, Raman scattering (Raman scattering) and infrared (IR) spectroscopy, as well as theoretically using the density functional theory (DFT). Eight Raman-active modes and twelve IR-active modes were detected and identified from consideration of the point group symmetry. Based on the analysis of the electronic spectrum and the density of states, the nature of the chemical bond in this semiconductor compound is determined. The theoretically calculated results are compared with the experimental data of the present work and with the results of experimental data available in the literature obtained by infrared spectroscopy and Raman scattering.

Theoretical determination of the structures of CaSiO3 perovskites

2006 ◽  
Vol 62 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
Razvan Caracas ◽  
Renata M. Wentzcovitch
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Determination ◽  
Functional Theory ◽  
Starting Point ◽  
Atomic Coordinates ◽  
The Ideal

Density functional theory is used to determine the possible crystal structure of the CaSiO3 perovskites and their evolution under pressure. The ideal cubic perovskite is considered as a starting point for studying several possible lower-symmetry distorted structures. The theoretical lattice parameters and the atomic coordinates for all the structures are determined, and the results are discussed with respect to experimental data.

Investigations of the Optical Properties of LaNi5 and LaNi4.5Sn0.5

2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.

First-Principles Study of Triangle Terarylene as a Possible Optical Molecular Switch

2011 ◽  
Vol 311-313 ◽  
pp. 526-529
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ji Xin Yin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Optical Switches ◽  
Functional Theory ◽  
Closed Ring ◽  
Potential Applications ◽  
Homo Lumo ◽  
Non Equilibrium Green’S Function ◽  
Theoretical Results

Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

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