Nuclear moments electric quadrupole

Nuclear electric quadrupole moment of ground (g) and excited (e) state (in... 

Bleaney, B., Bowers, K.D., and Pryce, M.H.L. 1955. Paramagnetic resonance in dilute copper salts III. Theory, and evaluation of the nuclear electric quadrupole moments of 63Cu and 65Cu. Proceedings of the Royal Society of London A 228 166-174. 

Extraframework cations are needed in anionic zeolites for charge balance, and for several zeolite topologies their locations are well investigated [281, 282]. Different cations have been investigated by solid state NMR in the past with different NMR properties and different project targets. We restrict this section to a tutorial example on sodium cation motion in sodalite and cancrinite structures [283-285], 23Na has a nuclear electric quadrupole moment, and quadrupolar interaction is useful to investigate jump processes, especially when they are well defined. 

In other words, isotopes having a spin value equal to, or greater than one exhibit an ellipsoidal charge distribution and have spin. They invariably possess a nuclear electric quadrupole moment, designated as Q ... 

There is another common cause of line splittings in microwave spectroscopy. Nuclei with spin I > 1 have an electric quadrupole moment. An electric quadrupole moment arises from a nonspherically symmetric charge distribution for example, a uniformly charged ellipsoid of revolution has no electric dipole moment, but does have an electric quadrupole moment. The nuclear electric quadrupole moment is16... 

The interaction between the nuclear electric quadrupole moment and the electrons of the molecule couples the nuclear spin I to the rotational angular momentum J, giving a resultant total angular momentum F, of... 

Yi and Ys - gyromagnetic ratio of spin 1 and spin S nuclear spin, rJS = intemuclear distance, tr= rotational correlation time, x< = reorientation correlation time, xj = angular momentum correlation time, Cs = concentration of spin S, Cq = e2qzzQ/h = quadrupole coupling constant, qzz = the electric field gradient, Q = nuclear electric quadrupole moment in 10 24 cm2, Ceff = effective spin-rotational coupling constant, a = closest distance of appropriate of spin 1 and spin S, D = (DA+DB)/2 = mutual translational self diffusion coefficient of the molecules containing I and S, Ij = moment of inertia of the molecule, Ao = a// - ol-... 

Static quadrupole effects in NMR are observed in solids (9) and also in anisotropic liquid crystals (10, 11, 12). For nuclei with spin quantum numbers, I, greater than V2, the distribution of positive charge over the nucleus can be nonspherical and the situation can be described in terms of a nuclear electric quadrupole moment. The interaction between the quadrupole moment, eQ and electric field gradients, eq, shifts the energy levels of the nuclear spin states. 

NMR spectra of quadrupolar nuclei are influenced by the interaction of the nuclear electric quadrupole moment with electrostatic field gradients generated at the nuclear sites by asymmetric electron distributions due to chemical bonding. To a first order... 

Table 3.3 Nuclear Spin /, Nuclear Gyromagnetic Ratio gN, Isotopic Abundance, Nuclear Electric Quadrupole Moment Q, and NMR Resonance Frequency v at 1 Tesla (10,000 Gauss) for Nuclei of Interest to NMR and NQRa...

Nuclear electric quadrupole moment interaction with electric field gradient... 

For chemically interesting nuclei, Table 11.10 lists values of the nuclear spin quantum number I, the nuclear gyromagnetic ratio gN/ the nuclear electric quadrupole moment Q, and the nuclear magnetic resonance frequency v (Hz, for H0 = 1 tesla). 

For nuclei with 7 1, the nuclear electric quadrupole moment interacts with the electric field gradient in a nonsymmetric environment of electrons around the nucleus. The electric field gradient is described by a tensor that can be expressed in diagonal form (components Vx, VY, and IQ) in a principal axis system fixed in the molecule. By Laplace s equation the sum of the three components is zero, so there are two independent parameters, usually taken as the largest of the three components, V7 = d2V/dz2, and the asymmetry parameter tj = (Vx — IQ)/ Vz, with the convention that VZ VX. The electrical interaction leads to... 

NMR relaxation method is a very powerful tool for the study of ionic interactions. Many nuclei studied are with spin quantum number I > 1/2 and their relaxations are governed by quadrupole interaction between the nuclear electric quadrupole moment and the electric field gradient (efg) at the nuclear site. Under extreme narrowing condition, the longitudinal... 

Electric Quadrupole Interaction (Quadrupole Splitting). This interaction exists when the electrons and/or the neighboring atoms produce an inhomogeneous electric field at the nucleus and when the nucleus possesses a quadrupole moment. The interaction between the nuclear electric quadrupole moment Q and the electric field gradient (EFG) is given by (15)... 

Although not all useful nuclei contained in organic compounds have been fully explored from the chemical point of view it is as well to point out that nuclear magnetic resonance methods can be applied to study all atoms which make up organic molecules. The resonances of the following nuclei can be observed H1, H2 and H3 (Tiers, 1964) F19 Nu and N1B O17 C13 P31 S33 B10 and B11 and Si29 (Pople et al., 1959). Many of these nuclei are present in low natural abundance (Varian Associates, 1964) and some have, in addition to a nuclear magnetic moment, a nuclear electric quadrupole moment (Pople et al., 1959). 

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