Log in

Relevant bibliographies by topics / Hartree-Fock (HF) theory / Journal articles

To see the other types of publications on this topic, follow the link: Hartree-Fock (HF) theory.

Journal articles on the topic 'Hartree-Fock (HF) theory'

Author: Grafiati

Published: 5 June 2025

Last updated: 1 August 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Hartree-Fock (HF) theory.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Cui, Qiang, and Marcus Elstner. "Density functional tight binding: values of semi-empirical methods in an ab initio era." Phys. Chem. Chem. Phys. 16, no. 28 (2014): 14368–77. http://dx.doi.org/10.1039/c4cp00908h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

BACH, VOLKER, ELLIOTT H. LIEB, and MARCOS V. TRAVAGLIA. "FERROMAGNETISM OF THE HUBBARD MODEL AT STRONG COUPLING IN THE HARTREE–FOCK APPROXIMATION." Reviews in Mathematical Physics 18, no. 05 (2006): 519–43. http://dx.doi.org/10.1142/s0129055x06002735.

Full text

Abstract:

As a contribution to the study of the Hartree–Fock theory, we prove rigorously that the Hartree–Fock approximation to the ground state of the d-dimensional Hubbard model leads to saturated ferromagnetism when the particle density (more precisely, the chemical potential μ) is small and the coupling constant U is large, but finite. This ferromagnetism contradicts the known fact that there is no magnetization at low density, for any U, and thus shows that HF theory is wrong in this case. As in the usual Hartree–Fock theory, we restrict attention to Slater determinants that are eigenvectors of the

APA, Harvard, Vancouver, ISO, and other styles

3

Yanai, Takeshi, George I. Fann, Gregory Beylkin, and Robert J. Harrison. "Multiresolution quantum chemistry in multiwavelet bases: excited states from time-dependent Hartree–Fock and density functional theory via linear response." Physical Chemistry Chemical Physics 17, no. 47 (2015): 31405–16. http://dx.doi.org/10.1039/c4cp05821f.

Full text

Abstract:

A fully numerical method for the time-dependent Hartree–Fock and density functional theory (TD-HF/DFT) with the Tamm–Dancoff (TD) approximation is presented in a multiresolution analysis (MRA) approach.

APA, Harvard, Vancouver, ISO, and other styles

4

Sharma, Bandana, Munish Kumar Yadav, and Shweta Prakash. "MOLECULAR STRUCTURE, EXPERIMENTAL AND THEORETICAL (HF, DFT) SPECTRAL ANALYSIS OF 3,4,5- TRIMETHOXYANILINE." RASAYAN Journal of Chemistry 16, no. 02 (2023): 905–20. http://dx.doi.org/10.31788/rjc.2023.1628371.

Full text

Abstract:

Experimental infrared and laser Raman spectra of 3,4,5-trimethoxyaniline were recorded in the first part of our investigation. Theoretically, using Hartree-Fock and density functional theory, structural properties and vibrational frequencies were estimated. The Hartree-Fock level spectral analysis was conducted using the HF/6-31+G(d,p) and HF/6-311++G(d,p) approaches. The B3LYP/6-31+G(d, p) technique was implemented to accomplish the DFT analysis. Comprehensive details of infrared, Raman intensity, scaled frequencies, reduced masses, and force constants are also presented in this paper. The vi

APA, Harvard, Vancouver, ISO, and other styles

5

Glushkov, A., V. Kovalchuk, A. Sofronkov, and A. Svinarenko. "OPTIMIZED QUASIPARTICLE DENSITY FUNCTIONAL APPROACH FOR MULTIELECTRON ATOMIC SYSTEMS." Photoelectronics, no. 29 (December 28, 2021): 38–44. http://dx.doi.org/10.18524/0235-2435.2020.29.225482.

Full text

Abstract:

We present the optimized version of the quasiparticle density functional theory (DFT), constructed on the principles of the Landau-Migdal Fermi-liquids theory and principles of the optimized one-quasiparticle representation in theory of multielectron systems. The master equations can be naturally obtained on the basis of variational principle, starting from a Lagrangian of an atomic system as a functional of three quasiparticle densities. These densities are similar to the Hartree-Fock (HF) electron density and kinetical energy density correspondingly, however the third density has no an analo

APA, Harvard, Vancouver, ISO, and other styles

6

SEVERIN, LUKAS, M. S. S. BROOKS, and BÖRJE JOHANSSON. "THEORY OF ORBITAL SPLITTING IN METALS." International Journal of Modern Physics B 07, no. 01n03 (1993): 255–57. http://dx.doi.org/10.1142/s021797929300055x.

Full text

Abstract:

A theory for orbital splitting is derived from a statistical Hartree-Fock (HF) treatment of open shell interactions. In a scaling procedure, where the HF spinpolarization matrix is replaced by the corresponding local spin density matrix, an expression for the orbital splitting is derived which is well suited for implementation in the standard ab initio calculational scheme. Results for Co metal as well as for the itinerant 5f ferromagnet US is presented, which are in good agreement with experiment.

APA, Harvard, Vancouver, ISO, and other styles

7

K h u d a y k u l o v, B., A. A b s a n o v, U. H o l i k u l o v, and B. I l t a z a r o v. "STUDY OF FORMAMIDE - WATER COMPLEXES WITH RAMAN SPECTROSCOPY AND THEORETICAL CALCULATIONS." 2022-yil, 3-son (133/1) ANIQ FANLAR SERIYASI 5, no. 129/2 (2021): 1–10. http://dx.doi.org/10.59251/2181-1296.v5.1292.878.

Full text

Abstract:

: In this work, the geometric optimization of molecular complexes in aqueous solutions of an isolated formamide molecule in three different methods: Hartree-Fock (HF), density function theory (DFT) and the second order Møller–Plesset (MP2) pertrubation theory studied on the set of bases 6-311++G (2d, p).

APA, Harvard, Vancouver, ISO, and other styles

8

Flórez, Edison, Alejandro F. Maldonado, Gustavo A. Aucar, Jorge David, and Albeiro Restrepo. "Microsolvation of methylmercury: structures, energies, bonding and NMR constants (199Hg,13C and17O)." Physical Chemistry Chemical Physics 18, no. 3 (2016): 1537–50. http://dx.doi.org/10.1039/c5cp04826e.

Full text

Abstract:

Hartree–Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH<sub>3</sub>Hg<sup>+</sup>) and up to three water molecules.

APA, Harvard, Vancouver, ISO, and other styles

9

Kandau, Herudi, Hanggara Sudrajat, Andreas Napitupulu, Syahrul Khairi, Zaky Al-Fatony, and Herman Siagian. "AB INITIO STUDY OF AMMONIA CLUSTERS: (NH₃)_n (n = 2-6)." Indonesian Journal of Chemistry 8, no. 3 (2010): 392–96. http://dx.doi.org/10.22146/ijc.21595.

Full text

Abstract:

Hydrogen bonded neutral clusters of ammonia, (NH3)n (n = 2-6), have been theoretically investigated employing the D95++(d,p) (and wherever necessary, higher) basis sets at the Hartree-Fock (HF) level as well as with second-order Møller-Plesset (MP2) perturbation theory. While the ammonia trimer and tetramer exhibit perfect molecular symmetries and are nonpolar, the pentamer and hexamer both optimize with slight deviations from perfect symmetries and are seen to posses marginal, but nonzero dipole moments. The (NH3)n linear clusters are seen to be chemically softer than the corresponding cyclic

APA, Harvard, Vancouver, ISO, and other styles

10

Blenski, T., and S. Morel. "Application of Hartree-Fock theory of fluctuations to opacity calculation." Laser and Particle Beams 13, no. 2 (1995): 255–69. http://dx.doi.org/10.1017/s026303460000937x.

Full text

Abstract:

The Hartree-Fock theory of fluctuations leading to simple formulae for configuration probabilities is used in a Detailed Configuration Accounting calculation of opacity in the case of an iron plasma. A direct Detailed Term Accounting method is also applied. The correlations of subshell occupation numbers, which are accounted for in the HF theory, show small effect on the theoretical spectrum corresponding to conditions of a recent measurement.

APA, Harvard, Vancouver, ISO, and other styles

11

Fliszár, S., N. Desmarais, and G. Dancausse. "Valence and core region energies of atoms in Hartree–Fock theory." Canadian Journal of Chemistry 70, no. 2 (1992): 537–46. http://dx.doi.org/10.1139/v92-076.

Full text

Abstract:

The subdivision of an atom into an inner core and an outer valence region reveals an interesting statistical aspect about the Hartree–Fock (HF) eigenvalues, εi, and the electron populations in the valence region, [Formula: see text] namely [Formula: see text] where Tv and [Formula: see text] are, respectively, the kinetic energy and the nuclear-electronic potential energy of the [Formula: see text] valence electrons, [Formula: see text] the interelectronic repulsion confined within the valence region, while [Formula: see text] is the repulsion between the core electrons and those of the valenc

APA, Harvard, Vancouver, ISO, and other styles

12

Zavodnik, Valery, Adam Stash, Vladimir Tsirelson, Roelof de Vries, and Dirk Feil. "Electron density study of urea using TDS-corrected X-ray diffraction data: quantitative comparison of experimental and theoretical results." Acta Crystallographica Section B Structural Science 55, no. 1 (1999): 45–54. http://dx.doi.org/10.1107/s0108768198005746.

Full text

Abstract:

The electron-density distribution in urea, CO(NH2)2, was studied by high-precision single-crystal X-ray diffraction analysis at 148 (1) K. An experimental correction for TDS was applied to the X-ray intensities. R merge(F 2) = 0.015. The displacement parameters agree quite well with results from neutron diffraction. The deformation density was obtained by refinement of 145 unique low-order reflections with the Hansen & Coppens [Acta Cryst. (1978), A34, 909–921] multipole model, resulting in R = 0.008, wR = 0.011 and S = 1.09. Orbital calculations were carried out applying different potenti

APA, Harvard, Vancouver, ISO, and other styles

13

Ojha, Tulsi, Susmita Limbu, Prakash Man Shrestha, Suresh Prasad Gupta, and Krishna Bahadur Rai. "Comparative Computational Study on Molecular Structure, Electronic and Vibrational Analysis of Vinyl Bromide based on HF and DFT Approach." Himalayan Journal of Science and Technology 7, no. 1 (2023): 38–49. http://dx.doi.org/10.3126/hijost.v7i1.61128.

Full text

Abstract:

In this study, we have used the Hartree-Fock and Density Functional Theory method of calculation and compared the equilibrium configuration, electronic and vibrational mode of Vinyl Bromide molecule. The molecule is geometrically optimized initially by using 6-31G basis set with B3LYP functional and then bond angles, bond lengths, dihedral angles and IR spectra are compared respectively. Various groups of atoms in Vinyl Bromide molecule by DFT has more accurate bond length, bond angle values rather than by HF computation when comparing with the experimental values. The ground state energies ar

APA, Harvard, Vancouver, ISO, and other styles

14

Tancic, Aleksandar, and M. Nikolic. "Dynamic response of some atoms: Many-body calculations." Facta universitatis - series: Physics, Chemistry and Technology 3, no. 2 (2005): 129–40. http://dx.doi.org/10.2298/fupct0502129t.

Full text

Abstract:

The frequency-dependent polarizability in the Hartree-Fock (HF) approximation has been corrected for true correlation effects by means of many-body theory. The polarizability has been computed in the Random Phase Approximation with Exchange (RPAE) for He, Ar Xe, Kr, Li, Ca through the second (and some higher) order in the correlation potential. With this polarizability as input we obtained the values of some atomic interaction constants.

APA, Harvard, Vancouver, ISO, and other styles

15

Lehtola, Susi, Frank Blockhuys, and Christian Van Alsenoy. "An Overview of Self-Consistent Field Calculations Within Finite Basis Sets." Molecules 25, no. 5 (2020): 1218. http://dx.doi.org/10.3390/molecules25051218.

Full text

Abstract:

A uniform derivation of the self-consistent field equations in a finite basis set is presented. Both restricted and unrestricted Hartree–Fock (HF) theory as well as various density functional approximations are considered. The unitary invariance of the HF and density functional models is discussed, paving the way for the use of localized molecular orbitals. The self-consistent field equations are derived in a non-orthogonal basis set, and their solution is discussed also in the presence of linear dependencies in the basis. It is argued why iterative diagonalization of the Kohn–Sham–Fock matrix

APA, Harvard, Vancouver, ISO, and other styles

16

Alzubadi, Ali A. "Investigation of the nuclear structure of 84-108Mo isotopes using Skyrme-Hartree-Fock method." Iraqi Journal of Physics (IJP) 13, no. 26 (2019): 1–11. http://dx.doi.org/10.30723/ijp.v13i26.278.

Full text

Abstract:

Over the last few decades the mean field approach using selfconsistentHaretree-Fock (HF) calculations with Skyrme effectiveinteractions have been found very satisfactory in reproducingnuclear properties for both stable and unstable nuclei. They arebased on effective energy-density functional, often formulated interms of effective density-dependent nucleon–nucleon interactions.In the present research, the SkM, SkM*, SI, SIII, SIV, T3, SLy4,Skxs15, Skxs20 and Skxs25 Skyrme parameterizations have beenused within HF method to investigate some static and dynamicnuclear ground state proprieties of 8

APA, Harvard, Vancouver, ISO, and other styles

17

Nishiyama, Seiya. "Resonating Relativistic Mean Field Theory of Finite Nuclei." International Journal of Modern Physics E 07, no. 05 (1998): 601–24. http://dx.doi.org/10.1142/s0218301398000348.

Full text

Abstract:

We develop a general theory based on relativistic fields to describe finite nuclei with large quantum fluctuations. The theory is a direct extension of the resonating Hartree-Fock (HF) and resonating Hartree-Bogoliubov (HB) theories to the relativistic mean field case including an effective nucleon mass and an effective potential mediated by mesons. We start from the Walecka model and construct coherent state representations of a system of nucleons described by Dirac spinors and of mesons described in terms of bosons. A state with large quantum fluctuations is approximated by superpositions of

APA, Harvard, Vancouver, ISO, and other styles

18

Masan, Samuel E. P. P., Fitri N. Febriana, Andi H. Zaidan, Ira Puspitasari, and Febdian Rusydi. "Evaluation of the Electronic Structure Resulting from ab-initio Calculations on Simple Molecules Using the Molecular Orbital Theory." Jurnal Penelitian Pendidikan IPA 7, no. 1 (2021): 107. http://dx.doi.org/10.29303/jppipa.v7i1.545.

Full text

Abstract:

Hartree Fock (HF) and Density Functional Theory (DFT) have been commonly used to model chemical problems. This study uses the Molecular Orbital Theory (MOT) to evaluate the electronic structure of five diatomic molecules generated by HF and DFT calculations. The evaluation provides an explanation of how the orbitals of a molecule come to be and how this affects the calculation of the physical quantities of the molecule. The evaluation is obtained after comparing the orbital wave functions calculated by MOT, HF, and DFT. This study found that the nature of the Highest Occupied Molecular Orbital

APA, Harvard, Vancouver, ISO, and other styles

19

Surbhi, Deeya Shalya, and Sarvendra Kumar. "Molecular Geometry, Homo-Lumo Analysis and Mulliken Charge Distribution of 2,6-Dichloro-4-Fluoro Phenol Using DFT and HF Method." East European Journal of Physics, no. 1 (March 2, 2023): 205–9. http://dx.doi.org/10.26565/2312-4334-2023-1-27.

Full text

Abstract:

 Phenolic compounds are used in human diet, commonly present in plants. Foremost polyphenolic compounds found in plants are flavanols, flavonoids, flavonones, iso-flavones, phenolic acids, flavonoids, chalcones, lignans etc. These compounds possess antimicrobial, antiviral and anti-inflammatory properties along with high antioxidative activity. The antioxidative activity of phenolic compounds depends on their structure. The polyphenols are very useful for the treatment of inflammation, cancer, anti-ageing purposes in cosmetic formulations, and nutraceutical applications. This article foc

APA, Harvard, Vancouver, ISO, and other styles

20

Sharma, Bandana, and Munish Kumar Yadav. "COMPUTATIONAL, EXPERIMENTAL SPECTRAL ANALYSIS AND STRUCTURAL PARAMETERS OF 4, 5-DIMETHYL-2- NITRO ANILINE." RASAYAN Journal of Chemistry 17, no. 03 (2024): 752–66. http://dx.doi.org/10.31788/rjc.2024.1738865.

Full text

Abstract:

The infrared and laser Raman spectra of 4, 5-dimethyl-2-nitroaniline were measured and used for experimental spectrum analysis for current work. On a computational level, Hartree-Fock and density functional theory were employed to perform geometry and vibrational spectral analysis. Here, scaled frequencies are displayed in addition to IR, Raman intensities, and decreased masses. Utilizing HF/6-31+G (d, p), HF/6-311++G (d, p), and B3LYP/6-31+G (d, p) approaches, the various thermodynamical parameters are tabulated. These include entropy, enthalpy, and specific heat. The geometrical footprints,

APA, Harvard, Vancouver, ISO, and other styles

21

Elhenawy, A. A., Mahmoud M. Abdel All, and Abd aziz A. Alomri. "Discovery anti-diabetic potent ofthiazolidinedione derivative based on virtual screening against aldose reducates." JOURNAL OF ADVANCES IN CHEMISTRY 10, no. 4 (2014): 2575–84. http://dx.doi.org/10.24297/jac.v10i4.895.

Full text

Abstract:

Thiazolidinedione (1) was used as a key intermediate for the synthesis of many therapeutic anti-diabetic molecule. Thus, Thiazolidinedione (1) was refluxed with aromatic aldehydes and phenol derivatives to afforded aryldine derivative (3). Moreover, the stereochemistry for compound 3 was discussed using Hartree-Fock theory geometries, and have been optimized at HF with 6-311G level of theory. The HOMO-LUMO energy gap of studied systems has been discussed. The molecular docking simulations into the active site of ALR2 were performed, and showed that, the compound 3 more suitable inhibitor again

APA, Harvard, Vancouver, ISO, and other styles

22

Avcı, Davut, Adil Başoğlu, and Yusuf Atalay. "Density Functional Theory and ab initio Hartree-Fock Calculations of Molecular Structure and Vibrational Spectra of Anilinium Nitrate." Zeitschrift für Naturforschung A 63, no. 10-11 (2008): 712–20. http://dx.doi.org/10.1515/zna-2008-10-1115.

Full text

Abstract:

The molecular geometry, vibrational frequencies, infrared intensities, Raman scattering activities and several thermodynamic parameters of anilinium nitrate in the ground state have been calculated by both Hartree-Fock (HF) and three density functional theory (DFT) methods (B3LYP, BLYP and B3PW91) using the 6-31G(d) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray structure. The optimized geometric bond lengths are described very well by the HF method while bond angles are reproduced more accurately by the DFT methods. Compariso

APA, Harvard, Vancouver, ISO, and other styles

23

Fatema, Kaniz. "Detection of Tetrachlorobutadiene Isomers Using Density Functional Theory Methods." Journal of Modeling and Simulation of Materials 7, no. 1 (2025): 1–17. https://doi.org/10.21467/jmsm.7.1.1-17.

Full text

Abstract:

The study aims to build upon previous research by incorporating Density Functional Theory (DFT), specifically using the B3LYP functional, to improve the computational methodology for analyzing chlorobutadiene (TCBD) compounds. DFT is chosen for its ability to account for electron correlation effects beyond the mean-field approximation, a limitation found in earlier approaches such as the Hartree-Fock (HF) method. By incorporating electron correlation, DFT provides a more accurate description of molecular properties, making it highly suitable for analyzing complex molecular structures like thos

APA, Harvard, Vancouver, ISO, and other styles

24

Bray, Igor, Xavier Weber, Dmitry V. Fursa, et al. "Taking the Convergent Close-Coupling Method beyond Helium: The Utility of the Hartree-Fock Theory." Atoms 10, no. 1 (2022): 22. http://dx.doi.org/10.3390/atoms10010022.

Full text

Abstract:

The convergent close-coupling (CCC) method was initially developed to describe electron scattering on atomic hydrogen and the hydrogenic ions such as He+. The latter allows implementation of double photoionization (DPI) of the helium atom. For more complex single valence-electron atomic and ionic targets, the direct and exchange interaction with the inner electron core needs to be taken into account. For this purpose, the Hartree-Fock (HF) computer codes developed in the group of Miron Amusia have been adapted. In this brief review article, we demonstrate the utility of the HF technique by exa

APA, Harvard, Vancouver, ISO, and other styles

25

A. Ibrahim, Ammar, and Mohammed Khahtan Hasan. "Theoretical Calculations of pKa Values for Substituted Carboxylic Acid." NTU Journal of Pure Sciences 1, no. 1 (2021): 19–26. http://dx.doi.org/10.56286/ntujps.v1i1.142.

Full text

Abstract:

Six different methods of determination have been used for studying ten derivatives of carboxylic compounds. Semi-empirical (AM1 and PM3), Hartree Fock (HF/STO-3G and HF/3-21G), and Density Function Theory (DFT/STO-3G and DFT/6-31G) were employed to calculate many physical theoretical parameters. The calculated data were correlated with experimental values of pKa using different regression(enter, stepwise and simple regression). Depending on the Fisher values, (HF/STO-3G) was shown as the best method for predicted of the pKa data compare to the (PM3) method using enter method. While (HF/3-21G)m

APA, Harvard, Vancouver, ISO, and other styles

26

Yahmin, Yahmin, Harno Dwi Pranowo, and Ria Armunanto. "AB INITIO INVESTIGATION OF 12-CROWN-4 AND BENZO-12-CROWN-4 COMPLEXES WITH Li⁺, Na⁺, K⁺, Zn²⁺, Cd²⁺, AND Hg²⁺." Indonesian Journal of Chemistry 10, no. 1 (2010): 106–9. http://dx.doi.org/10.22146/ijc.21488.

Full text

Abstract:

The structure and binding energies of 12-crown-4 and benzo-12-crown-4 complexes with Li+, Na+, K+, Zn2+, Cd2+, and Hg2+were investigated with ab initio calculations using Hartree-Fock approximation and second-order perturbation theory. The basis set used in this study is lanl2mb. The structure optimization of cation-crown ether complexes was evaluated at HF/lanl2mb level of theory and interaction energy of the corresponding complexes was calculated at MP2/lanl2mb level of theory (MP2/lanl2mb//HF/lanl2mb). Interactions of the crown ethers and the cations were discussed in term of the structure

APA, Harvard, Vancouver, ISO, and other styles

27

Joshi, Bhawani Datt, Poonam Tandon, and Sudha Jain. "Molecular characterization of yohimbine hydrochloride using vibrational spectroscopy and quantum chemical calculations." BIBECHANA 8 (January 15, 2012): 73–80. http://dx.doi.org/10.3126/bibechana.v8i0.4923.

Full text

Abstract:

In this work, we have performed the extraction of yohimbine hydrochloride (C21H27ClN2O3) (YHCl). The optimized geometry, total energy, potential energy surface and vibrational wavenumbers of YHCl have been determined by using ab initio Hartree–Fock (HF) and density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set. The calculated wavenumbers are scaled by a proper scaling factor. A selected number of vibrational assignments are provided for the observed Raman and IR spectra. Keywords: YHCl; vibrational spectroscopy; ESP; ab initio and DFT calculationsDOI: http://dx.doi.org/10.3

APA, Harvard, Vancouver, ISO, and other styles

28

Joshi, Bhawani Datt, Poonam Tandon, and Sudha Jain. "Structure, MESP and HOMO-LUMO study of 10-Acetyl- 10H-phenothiazine 5-oxide using vibrational spectroscopy and quantum chemical methods." BIBECHANA 9 (December 6, 2012): 38–49. http://dx.doi.org/10.3126/bibechana.v9i0.7151.

Full text

Abstract:

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/b

APA, Harvard, Vancouver, ISO, and other styles

29

Apriliyanto, Yusuf Bramastya, and Naufan Nurrosyid. "Comparative Analysis of Electronic Structures Calculations: A Simple Test Case Set for Kohn-Sham Density Functional Theory and Hartree-Fock Methods." Indonesian Journal of Chemical Studies 2, no. 2 (2023): 54–60. http://dx.doi.org/10.55749/ijcs.v2i2.33.

Full text

Abstract:

A comparative analysis on the performance of Kohn-Sham density functional theory (KS-DFT) and Hartree-Fock (HF) methods to obtain reliable energy and electronic properties has been performed in this study using a simple test case. It is crucial to re-emphasize the key differences between these methods to address common conceptual difficulties that occur among freshmen studying basic computational chemistry. The results suggested that the eigenvalue theorem in determining ionization potential could be well implemented in the HF but not in the KS-DFT method. The total energy difference between i

APA, Harvard, Vancouver, ISO, and other styles

30

Sen, K. D., P. C. Schmidt та Alarich Weiss. "Sternheimer Antishielding Functions ß(r) and γ(r) for Rare Earth Atoms". Zeitschrift für Naturforschung A 41, № 1-2 (1986): 37–46. http://dx.doi.org/10.1515/zna-1986-1-208.

Full text

Abstract:

The Sternheimer shielding-antishielding functions ß(r) and γ(r) are reported for all the fourteen lanthanide atoms at the uncoupled Hartree-Fock level of theory. Each atom is considered in two valence state configurations, 4fn 5d0 and 4 fn-1 5d1, and the nonrelativistic HF wave functions have been used. The 5d1 configuration leads to a smaller net antishielding than the 4fn configuration by ~ 6-12% in the series. The electron-electron self consistency effects are found to be less than 5% in the series. The importance of the calculated antishielding functions in the antishielding theory of elec

APA, Harvard, Vancouver, ISO, and other styles

31

Arief, Ihsanul, Ria Armunanto, and Bambang Setiaji. "STUDY ON ANTI-HIV ACTIVITY OF DIARYLANILINE DERIVATIVES USING QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP (QSAR)." Indonesian Journal of Chemistry 13, no. 2 (2013): 129–35. http://dx.doi.org/10.22146/ijc.21295.

Full text

Abstract:

Study on anti-HIV activity of diarylaniline derivative compounds by using quantitative structure-activity relationship (QSAR) has been done. The compounds structure and their anti-HIV activities were obtained from literature. Molecular and electronic parameters were calculated by Austin Model 1 (AM1), Parameterized Model 3 (PM3), Hartree-Fock (HF), and density functional theory (DFT) methods. QSAR analysis was performed using multilinear regression method. The result shows that HF method can produce the best model as follows:log EC50 = 46.418 + (99.360 × qC4) - (67.189 × qC9) - (278.869 × qC15

APA, Harvard, Vancouver, ISO, and other styles

32

Yu, Jia, Yu Cao, Hang Song, Xianlong Wang, and Shun Yao. "Calculations of optical rotation: Influence of molecular structure." Journal of the Serbian Chemical Society 77, no. 7 (2012): 887–98. http://dx.doi.org/10.2298/jsc110905207y.

Full text

Abstract:

Ab initio Hartree-Fock (HF) method and Density Functional Theory (DFT) were used to calculate the optical rotation of 26 chiral compounds. The effects of theory and basis sets used for calculation, solvents influence on the geometry and values of calculated optical rotation were all discussed. The polarizable continuum model, included in the calculation, did not improve the accuracy effectively, but it was superior to ?s. Optical rotation of five or sixmembered of cyclic compound has been calculated and 17 pyrrolidine or piperidine derivatives which were calculated by HF and DFT methods gave a

APA, Harvard, Vancouver, ISO, and other styles

33

Mohandass, P., S. Perumal, S. T. R. Dhanasekaran, P. Padmavathi, and K. K. Mothilal. "Spectroscopic Investigations, Computational Studies and Molecular Properties of Naphthalene Derivatives." Shanlax International Journal of Arts, Science and Humanities 9, S1-May (2022): 47–69. http://dx.doi.org/10.34293/sijash.v9is1-may.5944.

Full text

Abstract:

Theoretical studies have been carried out on bio active molecules such as Naphthalene (npa) and its derivatives naphthalene-2-sulfonic acid (nsa) and 1-nitroso-2-naphthol (nnol) using both Ab initio HF and DFT-B3LYP methods with 6-311++G(d,2p) basis sets. The geometrical parameters, molecular properties and vibrational spectra of nsa, nnol and npa were calculated and analyzed. Geometrical optimizations of the nsa, nnol and npa molecules were done by Density Functional Theory (DFT) using the B3LYP function and Hartree-Fock (HF) level with 6-311++G(d,2p) basis set. The optimized molecular geomet

APA, Harvard, Vancouver, ISO, and other styles

34

JORGE, F. E., L. M. BERNARDO, and E. P. MUNIZ. "CALCULATIONS WITH CORRELATED MOLECULAR WAVE FUNCTIONS: HF, MP2 AND DFT CALCULATIONS ON SECOND-ROW DIATOMIC HYDRIDES." Journal of Theoretical and Computational Chemistry 05, no. 02 (2006): 223–33. http://dx.doi.org/10.1142/s0219633606002179.

Full text

Abstract:

The performance of the previously proposed double zeta valence quality plus polarization functions (DZP) and augmented DZP (ADZP) basis sets is tested at the Hartree–Fock, second-order Møller–Plesset, and density functional levels of theory for the electronic ground state of the second-row diatomic hydrides. Total energy, second-order correlation energy, dissociation energy, bond length, vibrational frequency, and dipole moment are calculated and compared with results obtained with popular basis sets reported in the literature. It is shown that the DZP and ADZP basis sets in general provides b

APA, Harvard, Vancouver, ISO, and other styles

35

Gnani, Elena, Susanna Reggiani, Renato Colle, and Massimo Rudan. "Calculation of Transport Parameters of SiO2 Polymorphs." VLSI Design 13, no. 1-4 (2001): 311–15. http://dx.doi.org/10.1155/2001/64901.

Full text

Abstract:

Silica polymorphs have been analyzed, that are similar to the amorphous phase of SiO2; specifically, the α- and β-quartz, and the α- and β-cristobalite have been addressed. Two different ab initio methods have been used to calculate the full-band structure and the electronic properties of the polymorphs. In particular, the Hartree-Fock (HF) and Density-Functional Theory (DFT) approaches have been selected. A comparison of the energy-band branches and DOS shapes is reported, showing the similarities of the electrical properties that characterize the polymorphs under study. Finally, some relevan

APA, Harvard, Vancouver, ISO, and other styles

36

Liu, FengLi, YongFang Zhao, XinYing Li, and FengYou Hao. "Ab Initio Study of Structure and Stability of M2Al2 (M = Cu, Ag, and Au) Clusters." Australian Journal of Chemistry 60, no. 3 (2007): 184. http://dx.doi.org/10.1071/ch06436.

Full text

Abstract:

Coinage metal aluminium clusters M2Al2 (M = Cu, Ag, and Au) were studied by Hartree–Fock (HF) and second-order Møller–Plesset perturbation theory (MP2) with pseudopotentials. It was found that the butterfly structure with C2v (1A1) symmetry is more stable than the planar structure, and Au2Al2 is the most stable of the title species. The binding energies and the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO–LUMO) gap are evaluated, which indicates that doping clusters M2Al2 are more stable than the pure clusters M4 (M = Cu, Ag, and Au). Electron correlatio

APA, Harvard, Vancouver, ISO, and other styles

37

Alias, Siti Hajar, Fazira Ilyana Abdul Razak, Sheela Chandren, Wai Loon Leaw, Riadh Sahnoun, and Hadi Nur. "Band Gap Energy of Periodic Anatase TiO2 System Evaluated with the B2PLYP Double Hybrid Functional." Malaysian Journal of Fundamental and Applied Sciences 20, no. 1 (2024): 179–89. http://dx.doi.org/10.11113/mjfas.v20n1.3223.

Full text

Abstract:

The electronic properties of anatase titanium dioxide (TiO2) materials are of paramount importance for photocatalytic application. Ab initio calculation is performed on anatase TiO2 with various cluster sizes and shape, using Gaussian 09 program employing the standard 6-311G(d) and 3-21G basis set. Hartree-Fock (HF) theory, exchange-functional of density functional theory including hybrid (B3LYP, B3PW91, PBE1PBE and PBEh1PBE) and double-hybrid (B2PLYP), together with 2nd order Møller-Plesset perturbation theory are used to predict the band gap energy of anatase TiO2. With the inclusion of long

APA, Harvard, Vancouver, ISO, and other styles

38

Amara, Sarah, Noureddine Tchouar, and Salah Belaidi. "Computational Study of some Double Headed Acyclo-C-Nucleosides." International Letters of Chemistry, Physics and Astronomy 61 (November 2015): 1–11. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.61.1.

Full text

Abstract:

In the present paper we have a focus in a study of theoretical characterization of three double headed acyclo-C-nucleosides, which are a recent target of experimental studies. The structural and electronic properties of double headed acyclo-C-nucleosides, 1,4-bis (3-mercapto-1H-1,2,4-triazol-5-yl) butane-1,2,3,4-tetrol, 1,4-bis (4-amino-5-mercapto-4H-1,2,4-triazol-3-yl) butane-1,2,3,4-tetrol and 5,5'-(1,2,3,4-tetrahydroxybutane-1,4-diyl) bis (1,3,4-oxadiazole-2(3H)-thione), have been investigated theoretically by performing semi-empirical molecular orbital, ab initio Hartree-Fock (HF) and Dens

APA, Harvard, Vancouver, ISO, and other styles

39

Amara, Sarah, Noureddine Tchouar, and Salah Belaidi. "Computational Study of some Double Headed Acyclo-C-Nucleosides." International Letters of Chemistry, Physics and Astronomy 61 (November 3, 2015): 1–11. http://dx.doi.org/10.56431/p-old94x.

Full text

Abstract:

In the present paper we have a focus in a study of theoretical characterization of three double headed acyclo-C-nucleosides, which are a recent target of experimental studies. The structural and electronic properties of double headed acyclo-C-nucleosides, 1,4-bis (3-mercapto-1H-1,2,4-triazol-5-yl) butane-1,2,3,4-tetrol, 1,4-bis (4-amino-5-mercapto-4H-1,2,4-triazol-3-yl) butane-1,2,3,4-tetrol and 5,5'-(1,2,3,4-tetrahydroxybutane-1,4-diyl) bis (1,3,4-oxadiazole-2(3H)-thione), have been investigated theoretically by performing semi-empirical molecular orbital, ab initio Hartree-Fock (HF) and Dens

APA, Harvard, Vancouver, ISO, and other styles

40

Saravanan, S. P., A. Sankar, and K. Parimala. "Spectroscopic investigations of 2,5-Difluoronitrobenzene using Hartree-Fock (HF) and density functional theory (DFT) calculations." Journal of Molecular Structure 1127 (January 2017): 784–95. http://dx.doi.org/10.1016/j.molstruc.2016.03.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Șen, İbrahim, Cem Burak Yildiz, and Akın Azizoğlu. "Nontemplate synthesis, characterization and theoretical study of tetraazamacrocycles." Analele Universitatii "Ovidius" Constanta - Seria Chimie 23, no. 1 (2012): 121–27. http://dx.doi.org/10.2478/v10310-012-0020-7.

Full text

Abstract:

Abstract The syntheses of new tetraaza macrocyclic compounds of variable ring sizes by non-template methods and their characterization with the help of elemental analysis and spectroscopic techniques (FT-IR, 1H-NMR, and 13C-NMR) have been reported in detail. The vibrational frequencies determined experimentally are compared with those obtained theoretically from density functional theory (DFT) and Hartree-Fock (HF) calculations. The comparisons between the experimental and theoretical results indicate that B3LYP level with both the 3-21G(d) and 6-31G+(d,p) basis sets is able to provide satisfa

APA, Harvard, Vancouver, ISO, and other styles

42

Sert, Yusuf, Fatih Ucun, and Mustafa Böyükata. "Ab Initio Hartree-Fock and Density Functional Theory Study on Molecular Structures, Energies, and Vibrational Frequencies of 2-Amino-3-, 4-, and 5-Nitropyridine." Zeitschrift für Naturforschung A 65, no. 1-2 (2010): 107–12. http://dx.doi.org/10.1515/zna-2010-1-212.

Full text

Abstract:

AbstractThe molecular structures, vibrational frequencies, and corresponding vibrational assignments of 2-amino-3-, 4-, and 5-nitropyridine have been calculated by using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-311++G(d,p) basis set level. The calculated vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) were found to be in well agreement with the experimental data. The comparison of the observed and the calculated results showed that the scaled B3LYP method is superior to the scaled HF method for both the vibration

APA, Harvard, Vancouver, ISO, and other styles

43

Abdullah, Hewa Y. "Potential energy curve and spectroscopic parameters of multi-charged LiF molecule." Canadian Journal of Physics 95, no. 11 (2017): 1122–26. http://dx.doi.org/10.1139/cjp-2017-0155.

Full text

Abstract:

In the study of the special properties of molecules, diatomic molecules are vital. Three quantum mechanics methods were used to calculate the optimised structure and total electronic energy of the LiF molecule; namely, the Hartree–Fock (HF), density functional theory (DFT), and coupled cluster singles and doubles (and triples) (CCSD(T)) methods. The optimised structure properties, such as diploe moment, spectroscopic constants, and vibrational frequency, were calculated, as well as the potential energy curves. This study found that the negative LiF molecule is more stable than the neutral LiF

APA, Harvard, Vancouver, ISO, and other styles

44

Thangarasu, S., V. Siva, A. Shameem, A. Murugan, S. Athimoolam, and S. Asath Bahadur. "Structural, Electronic, Molecular Orbital Analysis and Charge Distributions on Nitrate Salt of Guanidine through DFT and TD-DFT Methods." Asian Journal of Chemistry 33, no. 8 (2021): 1905–10. http://dx.doi.org/10.14233/ajchem.2021.23201.

Full text

Abstract:

Guanidinium nitrate, a non-linear optical material has been systematically studied through quantum chemical (density functional theory and Hartree Fock) methods. Studies on Mulliken charge, Frontier molecular orbitals (FMOs) and hyperpolarizability analyses have been performed. The Mulliken population analyses were carried out for the optimized molecular geometry by HF and B3LYP methods with 6-311++G(d,p) levels. The molecular orbital parameters of guanidinium nitrate have been calculated by FMO analysis. Frontier molecular orbital (FMO) analysis indicates the electron delocalization on the gu

APA, Harvard, Vancouver, ISO, and other styles

45

Monajjemi, M., A. Nouri, and H. Monajemi. "QM AND AB INITIO INVESTIGATION ON THE HYDROGEN BONDING, NMR CHEMICAL SHIFTS AND SOLVENT EFFECTS ON THE DPPE." Indonesian Journal of Chemistry 7, no. 3 (2010): 260–72. http://dx.doi.org/10.22146/ijc.21667.

Full text

Abstract:

The hydrogen bonding effects that were produced from interaction of membrane lipid dipalmitoylphosphatidyl-ethanolamine (DPPE) with 1-5 water molecules, has been theoretically investigated through the quantum mechanical calculations at the Hartree-Fock level of theory and the 3-21G, 6-31G and 6-31G* basis sets with the computational package of Gaussian 98. According to the obtained results of the structural optimization of the isolated DPPE in the gas phase, we can see the evidences of interactions in the head group of this macromolecule (from the molecular point of view we have a proton trans

APA, Harvard, Vancouver, ISO, and other styles

46

Giarrusso, Sara, and Aurora Pribram-Jones. "Comparing correlation components and approximations in Hartree–Fock and Kohn–Sham theories via an analytical test case study." Journal of Chemical Physics 157, no. 5 (2022): 054102. http://dx.doi.org/10.1063/5.0097095.

Full text

Abstract:

The asymmetric Hubbard dimer is a model that allows for explicit expressions of the Hartree–Fock (HF) and Kohn–Sham (KS) states as analytical functions of the external potential, Δ v, and of the interaction strength, U. We use this unique circumstance to establish a rigorous comparison between the individual contributions to the correlation energies stemming from the two theories in the { U, Δ v} parameter space. Within this analysis of the Hubbard dimer, we observe a change in the sign of the HF kinetic correlation energy, compare the indirect repulsion energies, and derive an expression for

APA, Harvard, Vancouver, ISO, and other styles

47

Simons, J., H. G. Thomas, S. R. Hall, and G. Raabe. "Synthesis and structure of, and bonding in some derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane." Acta Crystallographica Section B Structural Science 57, no. 1 (2001): 63–71. http://dx.doi.org/10.1107/s0108768100013331.

Full text

Abstract:

Five derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane were synthesized and their molecular structures in the solid state were determined by means of X-ray diffraction analysis. In addition, the structures of all the molecules were optimized at different levels of computational quantum chemistry (HF/6-31G*, B3LYP/6-31G*). Experimentally determined bond lengths were compared with their calculated counterparts, and striking differences between the Hartree–Fock (HF) results and the experimental data could be traced back to the lack of correlation energy in the geometry optimizations. Two

APA, Harvard, Vancouver, ISO, and other styles

48

Boulakoud, Manel, Abdelkader Chouaih, and Fodil Hamzaoui. "Molecular structure investigation by ab initio, DFT and X-ray diffraction of thiazole-derived compound." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1234. http://dx.doi.org/10.1107/s2053273314087658.

Full text

Abstract:

We report here the synthesis of Z-3-(2-Ethoxyphenyl)-2-(2-Ethoxyphenyl)-1,3-Thiazolidin-4-one compound. The crystal structure has been determined by X-ray diffraction. The compound crystallizes in the monoclinic system with space group P21/n and cell parameters: a = 9.4094(10), b = 9.3066(10), c = 20.960(2) Å, β=99.0375(10)0, V = 1812.7(3)Å3 and Z = 4. The structure has been refined to a final R = 0.05 for 2083 observed reflections. The refined structure was found to be significantly non planar. The molecule exhibits intermolecular hydrogen bond of type C–H...O, C–H...N and C–H...S. Ab initio

APA, Harvard, Vancouver, ISO, and other styles

49

Bégué, Didier, Jean-marc Sotiropoulos, Claude Pouchan, and Daisy Y. Zhang. "Prediction of the photoelectron spectrum for XPY2 (X = H, F, Cl; Y = O, S) type of molecules by ab initio and DFT methods." Canadian Journal of Chemistry 84, no. 1 (2006): 5–9. http://dx.doi.org/10.1139/v05-257.

Full text

Abstract:

The present study reports the theoretical vertical ionization potentials (IPs) for all the valence electrons in six XPY2 molecules by utilizing the corrected orbital energies calculated with three theoretical methods, namely, the ab initio HartreeFock (HF), and both the pure and hybrid density functional theory (DFT) methods at, respectively, the BLYP/6-311+G* and B3lYP/6-311+G* levels of theory. Evaluation of the numerical corrections to the orbital energies was achieved by comparisons with the IP values obtained via explicit computation of the energy differences between the neutral molecule

APA, Harvard, Vancouver, ISO, and other styles

50

SIKORSKA, CELINA, DOROTA IGNATOWSKA, SYLWIA FREZA, and PIOTR SKURSKI. "THE PERFORMANCE OF SELECTED AB INITIO METHODS IN ESTIMATING ELECTRON BINDING ENERGIES OF SUPERHALOGEN ANIONS." Journal of Theoretical and Computational Chemistry 10, no. 01 (2011): 93–109. http://dx.doi.org/10.1142/s0219633611006293.

Full text

Abstract:

The capability of reproducing the vertical electron detachment energies (VDE) of four representative superhalogen anions was tested using the selected ab initio (Hartree-Fock (HF), second, third, and fourth-order Møller-Plesset perturbational scheme (MP2, MP3, MP4), coupled-cluster CCSD(T), and outer valence Green function (OVGF)) methods together with the variety of one-electron basis sets. Certain theoretical treatments (e.g. MP2/aug–cc–pVTZ and MP2/6-311+G(3df)) were found to be satisfactory for preliminary estimates of electron binding energies of superhalogen anions, whereas the use of th

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!