Distributed Gaussian basis sets: description of the Hartree-Fock ground state energies of N2, CO and BF using s- and p-type Gaussian functions

1995 ◽  
Vol 85 (1) ◽  
pp. 103-120 ◽  
Author(s):  
D. Moncrieff ◽  
S. Wilson
Keyword(s):  
Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Gaussian Functions ◽  
Hartree Fock ◽  
P Type ◽  
Ground State Energies

Gaussian basis sets for the atoms from K through Xe

2001 ◽  
Vol 79 (2) ◽  
pp. 121-123 ◽  
Author(s):  
R Centoducatte ◽  
E VR de Castro ◽  
F E Jorge
Keyword(s):  
Key Words ◽  
Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Generator Coordinate ◽  
Discretization Technique ◽  
Total Energies

An improved generator coordinate Hartree-Fock (IGCHF) method is used to generate Gaussian basis sets for the atoms from K (Z = 19) through Xe (Z = 54). The Griffin-Hill-Wheeler-HF equations are integrated using the integral discretization technique. The ground state HF total energies obtained by us are compared with those calculated with the original GCHF method and with other approaches reported in the literature. The largest difference between our energy values and the corresponding ones computed with a numerical HF method is equal to 6.003 mhartree for Kr (Z = 36).Key words: improved generator coordinate Hartree-Fock method, Gaussian basis sets, total energies.

Simplified Non-Empirical Unrestricted Hartree-Fock Approximation (SUHF) for the Calculation of Electronic Ground State Properties of Molecules with Closed and Open Valence Shells. II. Diatomic Molecules

1993 ◽  
Vol 48 (7) ◽  
pp. 834-840
Author(s):  
Wolfhard Koch ◽  
Klaus Neymeyr ◽  
Markus Pernpointner ◽  
Barbara Schaper ◽  
Klaus Strecker
Keyword(s):  
Ground State ◽  
Diatomic Molecules ◽  
Electronic Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Atomic Spin ◽  
Hartree Fock ◽  
Total Energies ◽  
Simplified Procedure ◽  
Electronic Ground

Abstract A comparison of numerical Simplified Unrestricted Hartree-Fock (SUHF) results (electronic ground state configurations, total energies, first ionization potentials, atomic charges, atomic spin densities of diatomic molecules) with those of equivalent standard calculations suggests the applicability of the non-empirical but drastically simplified procedure. SUHF may even approach ab initio quality obtained with simple (STO-3G) contracted Gaussian basis sets.

scholarly journals Accurate Gaussian basis sets for the ground state of the CS molecule

2005 ◽  
Vol 35 (4a) ◽  
pp. 965-970 ◽  
Author(s):  
M. T. Barreto ◽  
E. P. Muniz ◽  
F. E. Jorge ◽  
R. Centoducatte
Keyword(s):  
Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets

Application of multireference linearized coupled-cluster theory to atomic and molecular systems

2018 ◽  
Vol 17 (02) ◽  
pp. 1850016 ◽  
Author(s):  
Jiang Yi ◽  
Feiwu Chen
Keyword(s):  
Ground State ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Vibration Frequencies ◽  
Electron Affinities ◽  
Proton Affinities ◽  
Coupled Cluster Theory ◽  
Molecular Systems ◽  
Ground State Energies ◽  
Second Order Perturbation Theory

Applications of the multireference linearized coupled-cluster single-doubles (MRLCCSD) to atomic and molecular systems have been carried out. MRLCCSD is exploited to calculate the ground-state energies of HF, H2O, NH3, CH4, N2, BF, and C2with basis sets, cc-pVDZ, cc-pVTZ and cc-pVQZ. The equilibrium bond lengths and vibration frequencies of HF, HCl, Li2, LiH, LiF, LiBr, BH, and AlF are computed with MRLCCSD and compared with the experimental data. The electron affinities of F and CH as well as the proton affinities of H2O and NH3are also calculated with MRLCCSD. These results are compared with the results produced with second-order perturbation theory, linearized coupled-cluster doubles (LCCD), coupled-cluster doubles (CCD), coupled-cluster singles and doubles (CCSD), CCSD with perturbative triples correction (CCSD(T)). It is shown that all results obtained with MRLCCSD are reliable and accurate.

scholarly journals Role of Exchange and Correlation in High-Harmonic Generation Spectra of H2, N2 and CO2: Real-Time Time-Dependent Electronic-Structure Approaches

2020 ◽  
Author(s):  
Emanuele Coccia ◽  
Eleonora Luppi ◽  
Carlo Federico Pauletti
Keyword(s):  
Real Time ◽  
Harmonic Generation ◽  
Density Functional ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Time Dependent ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Exchange And Correlation

<p>This study arises from the attempt to answer the following question: how different descriptions of electronic exchange and correlation affect the high-harmonic generation (HHG) spectroscopy of H2, N2 and CO2 molecules? We compare HHG spectra for H2, N2 and CO2 with different ab initio electronic structures methods: real-time time-dependent configuration interaction (RT-TDCIS) and real-time time-dependent density functional theory (RT-TDDFT) using truncated basis sets composed of correlated wave functions expanded on Gaussian basis sets. In the framework of RT-TDDFT, we employ PBE and LC-ωPBE functionals. We study HHG spectroscopy by disentangling the effect of electronic exchange and correlation. We first analyse the electronic exchange alone and in the case of RT-TDDFT with LC-ωPBE, we use ω = 0.3 and ω = 0.4 to tune the percentage of long-range Hartree-Fock exchange and of short-range exchange PBE. Then, we added the correlation as described by PBE functional. All the methods give very similar HHG spectra and they seem not to be particularly sensitive to the different description of exchange and correlation or to the correct asymptotic behaviour of the Coulomb potential. Despite this general trend, some differences are found in the region connecting the cutoff and the background. Here, the harmonics can be resolved with different accuracy depending on the theoretical schemes used. We believe that the investigation of the molecular continuum and its coupling with strong fields merits further theoretical investigations in the next future. </p>

Improvement of the long-range behavior of Gaussian basis sets using asymptotic constraints

1992 ◽  
Vol 70 (2) ◽  
pp. 362-365 ◽  
Author(s):  
Toshikatsu Koga ◽  
Ajit J. Thakkar
Keyword(s):  
Long Range ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Atomic Orbitals ◽  
Hartree Fock

It is suggested that atomic orbitals with improved long-range behavior can be obtained by using energy-optimized Gaussian basis sets to which Gaussians have been added to satisfy a subset of some recently derived constraints that must be satisfied by the exact Hartree–Fock orbitals. This procedure is demonstrated by illustrative calculations for helium. This method is found to be superior to the adhoc method of adding diffuse Gaussians in an even-tempered fashion. Keywords: Gaussian basis sets, long-range behavior, asymptotic constraints.

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