The prediction of nuclear quadrupole moments fromabinitioquantum chemical studies on small molecules. II. The electric field gradients at the17O,35Cl, and2H nuclei in CO, NO+, OH−, H2O, CH2O, HCl, LiCl, and FCl

1987 ◽  
Vol 87 (1) ◽  
pp. 416-423 ◽  
Author(s):  
Peter L. Cummins ◽  
George B. Bacskay ◽  
Noel S. Hush
Keyword(s):  
Electric Field ◽  
Small Molecules ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Chemical Studies ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Moments

The nuclear quadrupole moment of 69Ga and 115In

2009 ◽  
Vol 87 (7) ◽  
pp. 802-805 ◽  
Author(s):  
Hana Yakobi ◽  
Ephraim Eliav ◽  
Uzi Kaldor
Keyword(s):  
Electric Field ◽  
Fock Space ◽  
Coupling Constants ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Moments

Electric field gradients at the nuclei of gallim and indium are determined by finite field calculations of the atomic energies as functions of the nuclear quadrupole moments. The four-component Dirac–Coulomb–Gaunt Hamiltonian serves as framework, and all electrons are correlated by Fock-space coupled cluster with single and double excitations or by single reference coupled cluster with approximate triples. Large, converged basis sets (e.g., 28s24p20d13f5g4h for In) and virtual spaces are used. Together with experimental nuclear quadrupole coupling constants, known with high precision, the calculated electric field gradients yield the nuclear quadrupole moments. For 69Ga, we get Q = 174(3) mb, in agreement with the earlier 171(2) mb obtained from molecular calculations. The 115In moment is Q = 772(5) mb, considerably lower than the previously accepted 810 mb, and in good agreement with the recent molecular value of 770(8) mb.

An ab initio Study of the Molecular Electric-field Gradients of the Chlorsilanes

1996 ◽  
Vol 51 (1-2) ◽  
pp. 41-45
Author(s):  
H. U. Suter ◽  
D. M. Maric ◽  
P. F. Meier
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Electron Correlation ◽  
Basis Sets ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Extended Basis ◽  
Good Agreement ◽  
Nuclear Quadrupole Moments

Abstract The electric field gradient (EFG) of chlorine in the chlorine containing silanes (SiCl4 , SiCl3H, SiCl2H2 , and SiClH3) was determined by means of ab initio methods and compared to recent experiments from which nuclear quadrupole moments are extracted. A careful estimation of the AO basis sets and the effect of the electron correlation is undertaken. The results showed the importance of the use of extended basis sets in the calculation of EFGs in second row atoms. Good agreement with deviations less than 5% from the experiments was found. The effect of the electron correlation was found to be small.

scholarly journals Investigation of the Negative Thermal Expansion of ZrW2O8

2000 ◽  
Vol 55 (1-2) ◽  
pp. 301-310 ◽  
Author(s):  
N. Ulbrich ◽  
W. Tröger ◽  
T. Butz ◽  
P. Blaha
Keyword(s):  
Thermal Expansion ◽  
Electric Field ◽  
Negative Thermal Expansion ◽  
Temperature Structure ◽  
Full Potential ◽  
Electric Field Gradients ◽  
Quadrupole Interactions ◽  
Nuclear Quadrupole Interactions ◽  
Field Gradients ◽  
Nuclear Quadrupole

The negative thermal expansion in ZrW2O8 was investigated on a microscopic scale by temperature dependent measurements of the electric field gradients at the nuclear probe 187W(β-) 187Re using time differential perturbed angular correlation spectroscopy. Two distinct nuclear quadrupole interactions I VzzRe1 l= 18.92(4) • 10 21 V/m2 , ηRe1 = 0.0 and I VzzRe1 l = 4.55(2) • 1021 V/m2 , ηRe1 = 0.053(3) were observed at 295 K, which are assigned to the two crystallographically distinct W0 4 tetrahedra of the room temperature structure. Ab initio calculations of electron densities and electric field gradients with 1:7 Re-impurities using the full potential linearized augmented plane wave package WIEN97 yield the electric field gradients VzzRe1 = 12.63 • 10 21 V/m2 , ηRe1 = 0.0 and VzzRe2 =4.90 • 10 21 V/m2 , ηRe2 =0.0. The observed temperature dependence of the nuclear quadrupole interactions agrees well with the structural phase transition at 428 K observed by neutron and x-ray diffraction. Our experiments corroborate the suggested mechanism of coupled librations of rigid ZrO6 octahedra and WO4 tetrahedra, which is an alternative description of transverse vibrations of oxygen atoms in Zr-O-W bonds, for the negative thermal expansion in ZrW2 O8

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