Coupling tensor nuclear quadrupole

Oxirane is an important Lewis base in the present context. The O atom carries two equivalent n-pairs of electrons, as it does in H20, but oxirane has the advantage over water in that it is possible to determine both angles 0 and 9 for its complexes with HC1 and ClF because the non-zero off-diagonal element Xab(Cl) of the Cl nuclear quadrupole coupling tensor is available. The corresponding Lewis base in which an S atom carries two equivalent n-pairs is thiirane. Each of the pair of complexes (CL S- -HC1 and (CL S- -ClF has Cs symmetry and here it is the off-diagonal element Xac(Cl) that is non-zero... 

Nuclear Quadrupole Coupling Tensors in Some Aluminosilicates... 

In 2008, Alonso and coworkers reported a combined experimental and computational study of the conformations of cysteine. They located 11 low lying conformers at MP4/6-311-i i-G(d,p)//MP2/6-311-l-l-G(d,p), and the five lowest energy structures are shown in Table 3.15. Using laser ablation molecular beam Fourier transform microwave spectroscopy, they identified six conformers present in the gas phase. Comparing the computed rotational constants and nuclear quadrupole coupling tensor components with the experiment, they were able to decidedly match up all six experimental conformers with computed structures. Of the five low energy conformers listed in Table 3.15, four of them were identified in the experiment. 

Dreizler and co-workers used quantum-chemical calculations at the MP4(SDQ) level to compute the nuclear quadrupole coupling tensor of in a series of molecules to compare them to values obtained from rotational spectra <1997ZNA297>. Improved values for thiirane are caa =—329425(78), ebb =—16.402(14), and ccc = 49.345(14) MHz, respectively. 

The analysis in Chapter 3 shows that fittings to the quantities G and P as a function of crystal orientation with respect to the magnetic field according to the Schonland method yield the elements of the hyperfine and nuclear quadrupole coupling tensors. A simple method therefore involves separate measurements of G and P from the observed ENDOR frequencies. 

ENDOR measurements of nuclear quadrupole coupling tensors of I > Vi nuclei A slightly lengthier analysis is required in the presence of nuclear quadrupole interactions, (nqi), from I > V2 nuclei. When the hyperfine and nuclear Zeeman interactions dominate over that caused by the nqi a simple method involves separate measurements of the parameters, G+ and P+ and/or G and P for ms = Vi of a free radical, as illustrated with the energy diagram in Fig. 3.11 for / = 1. 

H. Behzadi, H.D. Esrafili, N.L. Hadipour, A theoretical study of O, N and H nuclear quadrupole coupling tensors in the real crystalline structure of acetaminophen, Chem. Phys. 333 (2007) 97. 

The microwave spectrum of SiCh formed by conproportionation of SiCU and solid Si has been recorded . The large asymmetry of the Cl nuclear quadrupole coupling tensor was accounted for by large rr-electron back-donation from Cl to Si. Emission from the products of reaction of excited P2,0 Ar atoms with SiCLj and with SiH2Cl2 in a EX2 discharge flow system has been attributed to phosphorescence from Bi SiCl2 on the basis of the vibrational spacings . 

A, B, and C are the rotational constants Xaa. Zbb. and Xcc are the diagonal elements of the nuclear quadrupole coupling tensor Pa. Fb. and are the electric dipole moment components... 

Xgg components of the nuclear quadrupole coupling tensor when asymmetries originate... 

Nr. Molecule V Nu- Nuclear quadrupole coupling tensor coniponents Ref. Varia, remarks See Tab.,... 

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