Many-Body Rayleigh-Schrödinger Perturbation calculations of the correlation energy of open shell molecules in the restricted Roothaan-Hartree-Fock formalism. Application to heats of reaction and energies of activation

1980 ◽  
Vol 56 (4) ◽  
pp. 315-328 ◽  
Author(s):  
Petr Čársky ◽  
Rudolf Zahradník ◽  
Ivan Hubač ◽  
Miroslav Urban ◽  
Vladimír
Keyword(s):  
Correlation Energy ◽  
Open Shell ◽  
Many Body ◽  
Hartree Fock ◽  
Heats Of Reaction ◽  
Schrödinger Perturbation

Correlation energy in triplet electronic states. Application of the many-body Rayleigh-Schrödinger perturbation theory in the restricted Roothaan-Hartree-Fock formalism

1981 ◽  
Vol 46 (6) ◽  
pp. 1324-1331 ◽  
Author(s):  
Petr Čársky ◽  
Ivan Hubač
Keyword(s):  
Wave Function ◽  
Perturbation Theory ◽  
Correlation Energy ◽  
Electronic States ◽  
Many Body ◽  
Third Order ◽  
Explicit Formulas ◽  
Hartree Fock ◽  
The Many ◽  
Schrödinger Perturbation

Explicit formulas over orbitals are given for the correlation energy in triplet electronic states of atoms and molecules. The formulas were obtained by means of the diagrammatic many-body Rayleigh-Schrodinger perturbation theory through third order assuming a single determinant restricted Roothaan-Hartree-Fock wave function. A numerical example is presented for the NH molecule.

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

Many-body perturbation theory with a restricted open-shell Hartree—Fock reference

1991 ◽  
Vol 187 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
Walter J. Lauderdale ◽  
John F. Stanton ◽  
Jürgen Gauss ◽  
John D. Watts ◽  
Rodney J. Bartlett
Keyword(s):  
Perturbation Theory ◽  
Open Shell ◽  
Many Body ◽  
Hartree Fock ◽  
Many Body Perturbation Theory

Restricted open‐shell Hartree–Fock‐based many‐body perturbation theory: Theory and application of energy and gradient calculations

1992 ◽  
Vol 97 (9) ◽  
pp. 6606-6620 ◽  
Author(s):  
Walter J. Lauderdale ◽  
John F. Stanton ◽  
Jürgen Gauss ◽  
John D. Watts ◽  
Rodney J. Bartlett
Keyword(s):  
Perturbation Theory ◽  
Open Shell ◽  
Theory Theory ◽  
Many Body ◽  
Hartree Fock ◽  
Many Body Perturbation Theory

CORRELATION ENERGY IN SMALL JELLIUM CLUSTERS

1996 ◽  
Vol 03 (01) ◽  
pp. 395-397 ◽  
Author(s):  
C. GUET ◽  
S.A. BLUNDELL
Keyword(s):  
Density Functional ◽  
Correlation Energy ◽  
Second Order ◽  
Many Body ◽  
Functional Theory ◽  
Hartree Fock ◽  
Ground State Correlation ◽  
Many Body Perturbation Theory ◽  
Interaction Screening ◽  
Positively Charged

The correlation energy of finite systems of electrons in a neutralizing spherical positively charged background (jellium) is investigated within various approximations. The correlation energy is defined with respect to the Hartree–Fock energy (with exact treatment of exchange). On one hand, the exact second-order energy contribution is calculated from many-body perturbation theory. On the other hand, a quasi-boson approximation to harmonic order only allows one to estimate the RPA ground-state correlation energy and to emphasize the relative importance of Coulomb-interaction screening corrections (ring diagrams). One finds that the second-order contribution accounts for most of the correlation energy. Comparisons with other approaches, such as density-functional theory and CI calculations, confirm this assertion.

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