scholarly journals Nuclear Magnetic Shielding Constants of Halogens in X- and XO4-(X = F, Cl, Br, I) – Relativistic and Electron-Correlation Effects –

2004 ◽  
Vol 3 (4) ◽  
pp. 153-158
Author(s):  
Hirotaka TANIMURA ◽  
Masahiko HADA
Keyword(s):  
Electron Correlation ◽  
Magnetic Shielding ◽  
Correlation Effects ◽  
Shielding Constants ◽  
Electron Correlation Effects ◽  
Nuclear Magnetic

Calculation of nuclear magnetic shieldings. IX. Electron correlation effects

1994 ◽  
Vol 100 (9) ◽  
pp. 6608-6613 ◽  
Author(s):  
H. Fukui ◽  
T. Baba ◽  
H. Matsuda ◽  
K. Miura
Keyword(s):  
Electron Correlation ◽  
Correlation Effects ◽  
Electron Correlation Effects ◽  
Nuclear Magnetic

MP2 calculation of nuclear magnetic shielding constants involving gauge-invariant bases

1988 ◽  
Vol 66 (7) ◽  
pp. 1781-1785 ◽  
Author(s):  
Edouard C. Vauthier ◽  
Michel Comeau ◽  
Simone Odiot ◽  
Sandor Fliszar
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Spin Rotation ◽  
Basis Set ◽  
Magnetic Shielding ◽  
Resonance Spectroscopy ◽  
Correlation Effects ◽  
Gauge Invariant ◽  
Atomic Orbitals ◽  
Shielding Constants ◽  
Nuclear Magnetic

Dia- and paramagnetic shielding constants of HF, NH3, N2, H2O, and CO were calculated in the 4-31G, 4-31G*, and 6-31G** bases, using gauge-invariant atomic orbitals. Correlation effects were evaluated by 2nd-order perturbation theory: while the diamagnetic contributions are virtually unaffected by correlation, the paramagnetic parts (σρ) are modified by ~10 ppm in the 6-31G** basis. With or without correlation, calculated σρ values differ significantly from results obtained from measured spin-rotation constants. However, improvements in the basis set descriptions and inclusion of correlation yield chemical shift values for 15N and 17O converging toward their experimental counterparts obtained from conventional nuclear magnetic resonance spectroscopy.

Quantifying electron-correlation effects in small coinage-metal clusters by ab initio calculations

2021 ◽  
Author(s):  
Victor Giovanni de Pina ◽  
Bráulio Gabriel Alencar Brito ◽  
Guo -Q Hai ◽  
Ladir Cândido
Keyword(s):  
Monte Carlo ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electron Correlation ◽  
Metal Clusters ◽  
Correlation Effects ◽  
Diffusion Monte Carlo ◽  
Coinage Metal ◽  
Electron Correlation Effects ◽  
Fixed Node

We investigate many-electron correlation effects in neutral and charged coinage-metal clusters Cun, Agn, and Aun (n = 1 − 4) by ab initio calculations using fixed-node diffusion Monte Carlo (FN-DMC)...

BS DFT and BS HDFT studies of CrCr sextuple bond from the viewpoint of electron correlation effects

2009 ◽  
Vol 109 (14) ◽  
pp. 3315-3324 ◽  
Author(s):  
Yasutaka Kitagawa ◽  
Yasuyuki Nakanishi ◽  
Toru Saito ◽  
Takashi Kawakami ◽  
Mitsutaka Okumura ◽  
...  
Keyword(s):  
Electron Correlation ◽  
Correlation Effects ◽  
Electron Correlation Effects

Nonnuclear Maxima in the Charge Density

1993 ◽  
Vol 48 (1-2) ◽  
pp. 127-133 ◽  
Author(s):  
Kenneth E. Edgecombe ◽  
Vedene H. Smith, Jr. ◽  
Florian Müller-Plathe
Keyword(s):  
Charge Density ◽  
Electron Density ◽  
Electron Correlation ◽  
Basis Set ◽  
Valence Shell ◽  
Correlation Effects ◽  
Electron Correlation Effects

Abstract Basis-set and electron-correlation effects on the appearance and disappearance of nonnuclear maxima in the electron density are examined in Li2 , Na2 , Na4 and Na5 . It is shown that nonnuclear attractors can be removed in all cases except Li2 . The appearance of a pseudoatom in a lithium molecule correlates remarkably well with the size of the region, in an atomic calculation, of V2r(r) for the valence shell of the atom. This and the fact that the pseudoatom is also present in the promolecule indicate that the pseudoatoms are remnants of, or in fact are portions of, atoms that are not perturbed enough in the molecule to remove an essentially atomic characteristic.

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