scholarly journals HYPERFINE STRUCTURE PARAMETERS FOR COMPLEX ATOMS WITHIN RELATIVISTIC MANY-BODY PERTURBATION THEORY

2021 ◽  
pp. 52-59
Author(s):  
M. Makushkina ◽  
O. Antoshkina ◽  
O. Khetselius

The calculational results for the hyperfine structure (HFS) parameters for the Mn atom (levels of the configuration 3d64s) and  the results of advanced calculating the HFS constants and nuclear quadrupole moment for the radium isotope are obtained on the basis of computing within the relativistic many-body perturbation theory formalism with a correct and effective taking into account the exchange-correlation, relativistic, nuclear and radiative corrections. Analysis of the data shows that an account of the interelectron correlation effects is crucial in the calculation of the hyperfine structure parameters.  The fundamental reason of physically reasonable agreement between theory and experiment is connected with the correct taking into account the inter-electron correlation effects, nuclear (due to the finite size of a nucleus), relativistic and radiative corrections. The key difference between the results of the relativistic Hartree-Fock Dirac-Fock and many-body perturbation theory methods calculations is explained by using the different schemes of taking into account the inter-electron correlations as well as nuclear and radiative ones.

1973 ◽  
Vol 7 (1) ◽  
pp. 51-59 ◽  
Author(s):  
James E. Rodgers ◽  
Taesul Lee ◽  
T. P. Das ◽  
Dennis Ikenberry

2016 ◽  
Vol 756 ◽  
pp. 283-288 ◽  
Author(s):  
Alexander Tichai ◽  
Joachim Langhammer ◽  
Sven Binder ◽  
Robert Roth

2020 ◽  
Author(s):  
Daniel Smith ◽  
Lori Burns ◽  
Andrew Simmonett ◽  
Robert Parrish ◽  
Matthew Schieber ◽  
...  

<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>


2006 ◽  
Vol 73 (4) ◽  
Author(s):  
R. Roth ◽  
P. Papakonstantinou ◽  
N. Paar ◽  
H. Hergert ◽  
T. Neff ◽  
...  

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