Uniform description of the helium isoelectronic series down to the critical nuclear charge with explicitly correlated basis sets derived from regularized Krylov sequences

2020 ◽  
Vol 153 (22) ◽  
pp. 224106
Author(s):  
Jerzy Cioslowski ◽  
Filip Prątnicki
Keyword(s):  
Nuclear Charge ◽  
Basis Sets ◽  
Isoelectronic Series ◽  
Explicitly Correlated ◽  
Helium Isoelectronic Series

scholarly journals The S66 Non-Covalent Interactions Benchmark Reconsidered Using Explicitly Correlated Methods Near the Basis Set Limit

2018 ◽  
Vol 71 (4) ◽  
pp. 238 ◽  
Author(s):  
Manoj K. Kesharwani ◽  
Amir Karton ◽  
Nitai Sylvetsky ◽  
Jan M. L. Martin
Keyword(s):  
Computational Cost ◽  
The Other ◽  
Basis Set ◽  
Basis Sets ◽  
Explicitly Correlated ◽  
Non Covalent Interactions ◽  
Explicitly Correlated Methods ◽  
The One ◽  
High Level ◽  
Covalent Interactions

The S66 benchmark for non-covalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 ‘high-level corrections’ are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66×8 problem set in particular, and for accurate calculations on non-covalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, whereas half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.

Systematically convergent basis sets for explicitly correlated wavefunctions: The atoms H, He, B–Ne, and Al–Ar

2008 ◽  
Vol 128 (8) ◽  
pp. 084102 ◽  
Author(s):  
Kirk A. Peterson ◽  
Thomas B. Adler ◽  
Hans-Joachim Werner
Keyword(s):  
Basis Sets ◽  
Explicitly Correlated

Optimized auxiliary basis sets for explicitly correlated methods

2008 ◽  
Vol 129 (18) ◽  
pp. 184108 ◽  
Author(s):  
Kazim E. Yousaf ◽  
Kirk A. Peterson
Keyword(s):  
Basis Sets ◽  
Explicitly Correlated ◽  
Explicitly Correlated Methods

Application of Cusp-Satisfying Orbitals to Some Two-Electron Systems

1972 ◽  
Vol 50 (17) ◽  
pp. 2887-2890
Author(s):  
J. E. Brown ◽  
D. P. Chong
Keyword(s):  
Electron Density ◽  
Hydrogen Molecule ◽  
Lithium Atom ◽  
Electron Systems ◽  
Isoelectronic Series ◽  
Helium Isoelectronic Series

The kind of cusp-satisfying orbitals used earlier for the lithium atom is tested on the helium isoelectronic series and the hydrogen molecule. Excellent values are obtained for the electron density at the nucleus, Qe(0), for the atoms. The results for various wavefunctions for the hydrogen molecule are not as systematic, but are still quite reasonable.

scholarly journals Atomic X-ray Transition Probabilities: A Comparison of the Dipole Length, Velocity and Acceleration Forms

1984 ◽  
Vol 37 (1) ◽  
pp. 45 ◽  
Author(s):  
HM Quiney ◽  
FP Larkins
Keyword(s):  
Transition Probabilities ◽  
Nuclear Charge ◽  
Principal Quantum Number ◽  
Dipole Transition ◽  
Final States ◽  
X Ray ◽  
Hartree Fock ◽  
Isoelectronic Series ◽  
Rydberg Electron ◽  
Dipole Length

The length, velocity and acceleration forms of the dipole transition operator are examined in calculations of diagram and satellite X-ray emission probabilities in the Ne + to Ar 9 + isoelectronic series. All calculations are within the relaxed nonrelativistic Hartree-Fock framework, using separately optimized numerical wavefunctions for the initial and final electronic states. Divergence between the alternative forms of the transition moment, as the principal quantum 'number of the Rydberg electron and nuclear charge are increased, is discussed in the context of electron correlation differences between the initial and final states.

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