Microwave spectrum, structure, nuclear quadrupole coupling constants of chlorine, and ab initio calculation of 2-chloropropionitrile

1997 ◽  
Vol 412 (1-2) ◽  
pp. 39-46 ◽  
Author(s):  
Teruhiko Ogata ◽  
Noriko Yamashita ◽  
Shigetoshi Takata
Keyword(s):  
Ab Initio ◽  
Ab Initio Calculation ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Spectrum Structure

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.

14N Nuclear Quadrupole Hyperfine Structure in the Microwave Spectrum of Methyl Azide, CH3N3

1989 ◽  
Vol 44 (7) ◽  
pp. 669-674 ◽  
Author(s):  
N. Heineking ◽  
M.C.L. Gerry
Keyword(s):  
Hyperfine Structure ◽  
Ab Initio Calculation ◽  
Structural Information ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
First Time

Abstract The 14N nuclear quadrupole hyperfine structure in the rotational spectra of three isotopic species of methyl azide, CH3 14N3, CH3 15N14N2, and CH3 14N2 15N, has been resolved using microwave Fourier transform spectroscopy. The quadrupole coupling constants of 14N at all three positions have been evaluated and are compared with those from an ab initio calculation in the literature.Since the spectra of the substituted species have been obtained for the first time, they have provided new structural information: the rotational constants are consistent with a structure in which the NNN chain is slightly bent.

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.

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