Nuclear shielding polarizabilities

We apply this technique to study the effect of the spin-orbit coupling on an NMR shielding tensor and the shielding polarizability of the xenon atom. The shielding polarizabilities are defined as the second derivatives of nuclear shielding constants with respect to an electric field E... 

Table IIH20 Proton nuclear shielding (In ppm) and CTOCD-DZ shielding polarizabilities (in ppm, an) for basis sets I-Ul,...

Rizzo et al reported in refs. (17,18) results of nuclear shieldings and their polarizabilities for the same compounds but including correlation effects. By inspection of those values, we conclude that correlation affects dramatically both, nuclear magnetic shieldings and their polarizabilities for the CO compound but it is not so much important for H2O and CH4 molecules. In the case of the H2O molecule, the basis sets employed here must be improved since it is evident that they are not suitable enough to provide results of the same accuracy as those taken from the literature. 

Our calculations do not include vibrational corrections. Bishop and Cybulski have computed them for nuclear magnetic shielding and shielding polarizabilities of CO (9). 

Allowing for the hypervirial relations (115) and (116) and for the identities (117) and (122), one can partition the nuclear shieldings into atomic terms, in much the same way as for polarizabilities and susceptibilities. Thus... 

Theoretical predictions have been presented for nuclear magnetic shielding polarizabilities in small size molecules, by which the change of shielding to first and second order in a spatially uniform electric field can be evaluated [4,7,23,24,26,28,37-45],... 

Linear Response (2nd rank tensor) Electric dipole polarizability, a, magnetic dipole susceptibihty, optical rotatory power, k, nuclear shielding tensor at... 

A number of static perturbations arise from internal interactions or fields, which are neglected in the nonrelativistic Born-Oppenheimer electronic Hamiltonian. The relativistic correction terms of the Breit-Pauli Hamiltonian are considered as perturbations in nonrelativistic quantum chemistry, including Darwin corrections, the mass-velocity correction, and spin-orbit and spin-spin interactions. Some properties, such as nuclear magnetic resonance shielding tensors and shielding polarizabilities, are computed from perturbation operators that involve both internal and external fields. 

MD trajectory based on empirical polarizable force field and performed quantum chemical calculations of hyperfine couplings, g- and ZFS tensors and nuclear shielding terms at the snapshot configurations. Thus obtained fluctuations of the molecular properties were used to estimate the Curie-type paramagnetic relaxation contribution (which is a paramagnetic analogue of the CSA relaxation in the diamagnetic systems) to the NMR relaxation of aqueous protons. 

Nuclear magnetic shieldings and shielding polarizabilities vary according to the equations... 

CO Molecule. Table I summarizes the results of the nuclear magnetic shielding and its polarizabilities for the carbon and oxygen atoms in CO. The molecule was placed along the z axis, with the positive direction from O to C, assuming the Ci symmetry group. 

Also it would be possible to determine experimentally the influence of the electron shell to the nuclear wave function (nuclear polarizability). The 1S-electrons in heavy atoms admix excited states to the ground state of the nucleus in the order of 10 3 [24]. This leads additionally to the diamagnetic shielding to observable differences in the order of 10 3 of the nuclear magnetic moments for different charge states. 

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