Restricted Hartree-Fock and unrestricted Hartree-Fock as reference states in many-body perturbation theory: a critical comparison of the two approaches

1991 ◽  
Vol 80 (4-5) ◽  
pp. 407-425 ◽  
Author(s):  
Petr Čársky ◽  
Ivan Hubač
Keyword(s):  
Perturbation Theory ◽  
Many Body ◽  
Hartree Fock ◽  
Critical Comparison ◽  
Many Body Perturbation Theory

scholarly journals Hartree–Fock many-body perturbation theory for nuclear ground-states

2016 ◽  
Vol 756 ◽  
pp. 283-288 ◽  
Author(s):  
Alexander Tichai ◽  
Joachim Langhammer ◽  
Sven Binder ◽  
Robert Roth
Keyword(s):  
Perturbation Theory ◽  
Ground States ◽  
Many Body ◽  
Hartree Fock ◽  
Many Body Perturbation Theory

scholarly journals Psi4 1.4: Open-Source Software for High-Throughput Quantum Chemistry

2020 ◽  
Author(s):  
Daniel Smith ◽  
Lori Burns ◽  
Andrew Simmonett ◽  
Robert Parrish ◽  
Matthew Schieber ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Quantum Chemistry ◽  
Open Source ◽  
Density Functional ◽  
Many Body ◽  
Hartree Fock ◽  
Large Numbers ◽  
Many Body Perturbation Theory ◽  
Infrastructure Project ◽  
Job Specification

<div> <div> <div> <p>Psi4 is a free and open-source ab initio electronic structure program providing Hartree–Fock, density functional theory, many-body perturbation theory, configuration interaction, density cumulant theory, symmetry-adapted perturbation theory, and coupled-cluster theory. Most of the methods are quite efficient thanks to density fitting and multi-core parallelism. The program is a hybrid of C++ and Python, and calculations may be run with very simple text files or using the Python API, facilitating post-processing and complex workflows; method developers also have access to most of Psi4’s core functionality via Python. Job specification may be passed using The Molecular Sciences Software Institute (MolSSI) QCSchema data format, facilitating interoperability. A rewrite of our top-level computation driver, and concomitant adoption of the MolSSI QCArchive Infrastructure project, make the latest version of Psi4 well suited to distributed computation of large numbers of independent tasks. The project has fostered the development of independent software components that may be reused in other quantum chemistry programs. </p> </div> </div> </div>

scholarly journals Hartree-Fock and many body perturbation theory with correlated realisticNNinteractions

2006 ◽  
Vol 73 (4) ◽  
Author(s):  
R. Roth ◽  
P. Papakonstantinou ◽  
N. Paar ◽  
H. Hergert ◽  
T. Neff ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Many Body ◽  
Hartree Fock ◽  
Many Body Perturbation Theory

scholarly journals THEORETICAL STUDYING EXCITED STATES SPECTRUM OF THE YTTERBIUM WITHIN THE OPTIMIZED RELATIVISTIC MANY-BODY PERTURBATION THEORY

2021 ◽  
pp. 118-125
Author(s):  
V. Ternovsky ◽  
A. Svinarenko ◽  
Yu. Dubrovskaya
Keyword(s):  
Perturbation Theory ◽  
Excited States ◽  
Theoretical Data ◽  
Zeroth Approximation ◽  
Relativistic Energy ◽  
Many Body ◽  
Hartree Fock ◽  
Ytterbium Atom ◽  
Many Body Perturbation Theory ◽  
Experimental Values

Theoretical studying spectrum of the excited states for the ytterbium atom is carried out within the relativistic many-body perturbation theory with ab initio zeroth approximation and generalized relativistic energy approach.  The zeroth approximation of the relativistic perturbation theory is provided by the optimized Dirac-Kohn-Sham ones. Optimization has been fulfilled by means of introduction of the parameter to the Kohn-Sham exchange potentials and further minimization of the gauge-non-invariant contributions into radiation width of atomic levels with using relativistic orbital set, generated by the corresponding zeroth approximation Hamiltonian. The obtained theoretical data on energies E and widths W of the ytterbium excited states are compared with alternative theoretical results (the Dirac-Fock, relativistic Hartree-Fock, perturbation  theories) and available experimental data. Analysis shows that the theoretical and experimental values ​​of energies are in good agreement with each other, however, the values ​​of widths differ significantly. In our opinion, this fact is explained by insufficiently accurate estimates of the radial integrals, the use of unoptimized bases, and some other approximations of the calculation.

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
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