Ab initio calculation of 14N and 35Cl nuclear quadrupole coupling constants in aziridine and Cl-aziridine

1993 ◽  
Vol 279 ◽  
pp. 29-34 ◽  
Author(s):  
O.D. Fominykh ◽  
M.Yu. Balakina ◽  
I.D. Morozova ◽  
D.Ya. Osokin
Keyword(s):  
Ab Initio ◽  
Ab Initio Calculation ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

14N Nuclear Quadrupole Coupling in Glycyl-Glycine and Related Peptides

1984 ◽  
Vol 39 (11) ◽  
pp. 1108-1111 ◽  
Author(s):  
Michael Palmer
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Ab Initio Calculation ◽  
Coupling Constants ◽  
Double Zeta ◽  
Quadrupole Coupling ◽  
Aromatic Systems ◽  
Nuclear Quadrupole ◽  
Glycyl Glycine

An ab initio calculation of double zeta quality on glycyl-glycine at the crystal structure yielded nuclear quadrupole coupling constants at the peptide centres very close to experiment; Xzz -3.03, Xyy +2.14, Xxx +0.89 MHz. The first two couplings lie in the local π-direction, and along the C-N bond, respectively. At the NH⊕3 centre the values were less satisfactory, but the (low) positive value of Xzz was obtained, and lies relatively close to the N-C bond. The results suggest that similar calculations may be successful for other H-bonded systems, provided that aromatic systems are not involved.

The ab initio Calculation of Nuclear Quadrupole Coupling Constants with Special Reference to 33S

1992 ◽  
Vol 47 (1-2) ◽  
pp. 203-216 ◽  
Author(s):  
Michael H. Palmer
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ab Initio Calculation ◽  
Coupling Constants ◽  
Basis Set ◽  
Equilibrium Geometry ◽  
Relaxation Methods ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
The Relationship

AbstractThe ab initio calculation of 33S nuclear quadrupole coupling constants (NQCC) for a range of S-containing compounds with S2, S4 and S6 bonding types is described. All of the calculations used a triple zeta valence + polarisation basis set (TZVP) of gaussian type orbitals; all of the molecules were studied at the TZVP equilibrium geometry. The electric field gradients (EFG) calculated were correlated with the experimental NQCC obtained by either microwave spectroscopy (MW), nuclear quadrupole resonance (NQR) or NMR relaxation methods; although the experimental data cover a wide diversity of chemical types over a long period of time, the slope of the relationship between the EFG (qii) and the NQCC (χii) yields a value for the 33S atomic quadrupole moment of - 0.064 barn, very close to recent calculations with a large atomic basis set, and to experimental data. The relationship between the EFG tensor components and the internal molecular structure features is discussed for a diverse series of molecules.

The ab initio Calculation of Nuclear Quadrupole Coupling Constants and their Comparison with Experiment

1990 ◽  
Vol 45 (3-4) ◽  
pp. 357-367 ◽  
Author(s):  
Michael H. Palmer
Keyword(s):  
Ab Initio ◽  
Single Molecule ◽  
Ab Initio Calculation ◽  
Coupling Constants ◽  
Structural Variations ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Comparison With Experiment ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract Ab initio calculations of electric field gradients (EFG) and conversion to nuclear quadrupole coupling constants (NQCC) are described, with particular reference to 14 N and 10,11B. The correlation of EFG and NQCC for a series of boranes leads to the value 8.32 MHz/a.u. (0.0354 barn) for Q(11B). The structural variations of these microwave and single molecule calculations of 10,11 B NQCC are discussed.

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