Quasi-degenerate many-body Rayleigh-Schrödinger perturbation theory

1975 ◽  
Vol 25 (4) ◽  
pp. 371-391 ◽  
Author(s):  
V. Kvasnička
Keyword(s):  
Perturbation Theory ◽  
Many Body ◽  
Schrödinger Perturbation

Brillouin-Wigner Perturbation Theory as a Possible more Effective Alternative to Many-Body Rayleigh-Schrodinger Perturbation Theory and Coupled Cluster Theory

1995 ◽  
Vol 60 (9) ◽  
pp. 1419-1428 ◽  
Author(s):  
Petr Čársky ◽  
Vojtěch Hrouda ◽  
Vladimír Sychrovský ◽  
Ivan Hubač ◽  
Peter Babinec ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Computational Methods ◽  
Effective Alternative ◽  
Coupled Cluster ◽  
View Point ◽  
Many Body ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Schrödinger Perturbation

Brillouin-Wigner perturbation theory is revisited using the Lippmann-Schwinger equation and applied to the H2O molecule. The results obtained are examined from the view-point of the development of practical computational methods.

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.

Ab initio calculations of the ground state potential function of the hydroxyl anion by means of the many-body Rayleigh-Schrödinger perturbation theory

1981 ◽  
Vol 46 (11) ◽  
pp. 2595-2599
Author(s):  
Ivan Kozák ◽  
Vladimír Špirko ◽  
Petr Čársky
Keyword(s):  
Perturbation Theory ◽  
Ground State ◽  
Negative Ions ◽  
Spectroscopic Constants ◽  
Many Body ◽  
Hydroxyl Anion ◽  
Wide Range ◽  
State Potential ◽  
The Many ◽  
Schrödinger Perturbation

Many-body Rayleigh-Schrödinger perturbation theory (MB-RSPT) up to third order applied to OH- in the range of interatomic distances from 0.0815 to 0.1175 nm. The energy data obtained are combined with the experimental RKR (ground state) potential of HF, and, a ground state potential of OH- is constructed (over a wide range of internuclear distances) within the framework of the reduced potential curve method. With the use of this potential the corresponding rotation-vibration Schrödinger equation is solved for 16OH-. The computed spectroscopic constants are compared with best reported calculations and available experimental evidence. The comparison indicates that MB-RSPT may be used as an adequate (and convenient) tool for the study of negative ions.

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