scholarly journals Nuclear quadrupole resonance measurement of the anisotropic magnetic shielding and quadrupole coupling constants ofEu3+151andEu3+153dilute in YAlO3single crystal

1981 ◽  
Vol 24 (7) ◽  
pp. 3697-3700 ◽  
Author(s):  
L. E. Erickson ◽  
K. K. Sharma
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Coupling Constants ◽  
Magnetic Shielding ◽  
Resonance Measurement ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

NQR Studies of the Structure of Glasses and Crystalline Compounds

1992 ◽  
Vol 47 (1-2) ◽  
pp. 30-38 ◽  
Author(s):  
P. J. Bray ◽  
DongHoon Lee ◽  
De Gen Mao ◽  
G. L. Petersen ◽  
S. A. Feller ◽  
...  
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Borate Glasses ◽  
Low Frequencies ◽  
Structure Of Glasses ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

AbstractPure nuclear quadrupole resonance (NQR) spectroscopy at low frequencies (down to 275 kHz) has been used to investigate a number of borate, aluminate, and vanadate crystalline compounds and borate glasses. The values of the quadrupole coupling constants (Qcc) and asymmetry parameters (η) are obtained with error limits that are one or two orders of magnitude less than those for values obtained from NMR spectra. New sites, not resolved in NMR spectra, have been detected for boron in borate glasses.

On the Correlation of 35Cl Nuclear Quadrupole Coupling Constants with π→γ3 and π→γ5 Optical Electron Transfer Bands of Transition Metal Complexes and its Significance in Pi-Bonding

1969 ◽  
Vol 24 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Paul Machmer
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Nuclear Quadrupole Resonance ◽  
Coupling Constants ◽  
Resonance Frequencies ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

From a consideration of odd-even intramolecular electron transfer processes in octahedrally co-ordinated transition metal complexes, two relationships have been derived. The first correlation describes π → γ3 optical electron transfer bands of the complexes K2OsCl6, K2IrCl6, K2PtCl6, K2PtCl4 as a function of the respective 35Cl nuclear quadrupole coupling constants. The second relationship correlates π → γ5 optical charge transfer transitions of the substances K2ReCl6, K2OsCl6, K2IrCl6 with the 35Cl nuclear quadrupole coupling constants of these compounds. By using this charge transfer model, a linear relationship has been verified between the optical electronegativity values of the quadrivalent transition metal ions W4⨁, Re4⊖, Os4⨁, Ir4⨁, Pt4⨁ and the 35Cl nuclear quadrupole coupling constants of their hexachloro complexes. The empirically established equation χMen+ = 0.537 which describes the 35Cl n.q.r. frequencies of the hexachloro complexes of Re4⨁, Os4⨁, Ir4⨁, Pt4⨁ and Pd4⨁ as a function of the optical electronegativity values χ of these metal ions, has been used to estimate 35Cl nuclear quadrupole resonance frequencies of chloro complexes as yet not probed by nuclear quadrupole resonance spectroscopy, e.g. Zeise's salt (KPtCl3C2H4), K3IrCl6, K2RuCl6, K3RhCl6 and K3MoCl6. Conversely, by the same procedure the optical electronegativity χ of W4⨁ and Au3⨁ has been estimated from the 35Cl quadrupole resonance frequency of K2WCl6 and KAuCl4 (χ W4⨁= 1.71 and χ Au3⨁=2.80). In the case of analogous bromo complexes, the equation χ Men+ = 0.19 mol accounts for the dependence of the 79Br nuclear quadrupole resonance frequencies upon the optical electronegativity of the metal ions. The assignment of electron transfer bands in other chloro complexes is discussed in the light of this “nuclear quadrupole resonance criterion“ of optical charge transfer bands.

The chemical interpretation and the temperature dependence of the 14N nuclear quadrupole resonance of aniline and several derivatives

1968 ◽  
Vol 46 (22) ◽  
pp. 3595-3604 ◽  
Author(s):  
C. T. Yim ◽  
M. A. Whitehead ◽  
Donald H. Lo
Keyword(s):  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Coupling Constants ◽  
Temperature Range ◽  
Resonance Frequencies ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Phenylene Diamine

The 14N nuclear quadrupole resonance frequencies of aniline, o- and p-phenylene diamine, and p-chloro-, p-bromo-, and p-iodo-aniline were measured with a super-regenerative oscillator over a temperature range from 77 to 292 °K. The temperature dependence is analyzed. The chemical interpretation of the quadrupole coupling constants and asymmetry parameters is described.

scholarly journals Nuclear Quadrupole Coupling in 5-Membered Ring Oxygen and Sulphur Heterocyclic Compounds; Studies by Nuclear Quadrupole Resonance and Ab Initio Molecular Orbital Calculations

1979 ◽  
Vol 34 (2) ◽  
pp. 220-232 ◽  
Author(s):  
Mavis Redshaw ◽  
Michael H. Palmer ◽  
Robert H. Findlay
Keyword(s):  
Ab Initio ◽  
Nuclear Quadrupole Resonance ◽  
Principal Axis ◽  
Coupling Constants ◽  
Molecular Orbital Calculations ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
High Level ◽  
Level Of Agreement

Abstract The 14N nuclear quadrupole resonance spectra for the compounds 2a, b, 3b, 4b, 5a, b, 6b have been obtained at 77 K and the asymmetry parameter and coupling constants extracted. A comparison of these with microwave spectral results, shows that small but systematic differences occur between the solid and gaseous states. There is a high level of agreement for the observed coupling constants from NQR or MW spectra and the ab initio calculations in both magnitude and direction. This enables us to extract further principal axis data from the observed microwave spectra, and to predict with some confidence the axes and coupling magnitudes for other members of the series where incomplete determinations are available. Variations in coupling constants with structure are discussed

The Charge Distribution in Amides and Thioamides by Nuclear Quadrupole Coupling, Dipole Moments and Electronic Structure Calculations

1996 ◽  
Vol 51 (5-6) ◽  
pp. 460-478
Author(s):  
Michael H. Palmer ◽  
Paul Sherwood
Keyword(s):  
Dipole Moments ◽  
Lone Pair ◽  
Coupling Constants ◽  
Hartree Fock ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Electron Contribution ◽  
Nuclear Quadrupole ◽  
Moller Plesset ◽  
Structure Calculations

AbstractThe nuclear quadrupole coupling constants from microwave spectroscopy (MW) and quadrupole resonance (NQR) for amides and thioamides are discussed in relation to Hartree-Fock calculations with and without Moller-Plesset correlation effects. The view that the larger dipole moments from thioamides than the corresponding amides is a function of enhanced resonance in the former is discussed and (in effect) confirmed by the present procedures. The principal mechamism seems to be the push/pull π/σ effects of the N atom with respect to the CO and CS groups, with S being a better σ-donor than O; however, the effect is still present with formamidine where no electronegativity effects are important, so the overall effect is the 2,1,1 π-electron contribution to the allylic system from N, C, O(S). The use of localised MO’s and NO’s is described, and the centroid positions are discussed in relation to the polarity of the bonds. The LMO’s largely truncate the contributions to each NQCC to the three attached bonds (or 2 bonds + a lone pair orbital at O or S), as is used in the Townes-Dailey procedures. More distant LMO’s generally contribute < 0.05 a. u. to the EFG, simplifying the analysis. The effects of O( or S)-protonation of urea and thiourea is discussed.

Second-moment nuclear quadrupole resonance measurement of in

1997 ◽  
Vol 9 (49) ◽  
pp. 10941-10950 ◽  
Author(s):  
Oscar A Nagel ◽  
Máximo E Ramia ◽  
Nestor R Veglio
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Second Moment ◽  
Resonance Measurement ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Nuclear Quadrupole Resonance of Antimony in Ln3Sb5O12 Crystals

1994 ◽  
Vol 49 (6) ◽  
pp. 687-689 ◽  
Author(s):  
A. M. Raevsky ◽  
A. G. Gukalova ◽  
G. K. Semin
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Compression Effect ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Lanthanide Compression

Abstract Complete 121,123Sb NQR spectra of crystalline rate earth antimonites Ln3Sb5O12 (Ln = La, Nd, Er, Lu) were recorded at 77 K. The quadrupole coupling constants and asymmetry parameters of the electric field gradient were measured. A “lanthanide compression” effect on the antimony NQR was observed. Using relations found for the antimonites under study, the Sb spectral parameters of other lanthanide compounds can be predicted.

14N nuclear quadrupole coupling in solid cinnolin-4-ones. A study by nuclear quadrupole resonance, x-ray crystallography and ab initio calculations

1987 ◽  
Vol 112 (2) ◽  
pp. 213-225 ◽  
Author(s):  
Michael H. Palmer ◽  
Robert O. Gould ◽  
Alexander J. Blake ◽  
John A.S. Smith ◽  
David Stephenson ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Nuclear Quadrupole Resonance ◽  
X Ray ◽  
X Ray Crystallography ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole
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