Susceptibility. Diamagnetic Shielding

The NFg radical is a slightly asymmetric (nearly prolate) top, A B C, with x= -0.94. The b axis coincides with the symmetry axis, and the c axis is perpendicular to the molecular plane. The coupling between the spin of the unpaired electron and the molecular rotation about the a, b, or c axis is accounted for by the spin-rotation constants (a = a, b, c). 

The rotational and spin-rotation constants for the ground state X Bi, v = 0 were obtained from analyses of the microwave (MW) spectrum [1 ] and of the highly resolved absorption lines (IR laser spectroscopy) of the vi fundamental band [2]. Constants for the vibrationally excited states Vi=1 [2] and Va=1 [3] were obtained from the IR laser spectra of the and V3 

Np2(X2Bi). Rotational Constants A, B, C, and Spin-Rotation Coupling Constants e a for the Vibrational Ground State and the Excited States Vi=1 and V3 = 1. 

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The one-electron properties such as the deuteron quadrupole coupling constant have been less studied until recently, but Dixon et al33 have recently reported the results for this property and also values of the diamagnetic shielding and susceptibility computed with a medium-size basis set. Moderate agreement with experiment was obtained. 

POLY ATOM programs and elsewhere the less obvious ones are tr, diamagnetic shielding F and FG, the electric field and field gradient at the nucleus x the diamagnetic susceptibility. Z is the internuclear axis. All properties are relative to the carbon atom origin and the values are in the global co-ordinate system and atomic units. 

Ab initio LCAO-MO-SCF calculations on the same species have given values for the electric field gradients, electric fields, diamagnetic shieldings, dipole moment, second moment, and diamagnetic susceptibility.155... 

The atomic hypothesis was investigated in an exhaustive manner by Maksic. He tested the the Independent Atoms in Molecule (lAM) and the Modified Atoms in Molecule (MAM) models for some simple physical observables as diamagnetic shielding, diamagnetic susceptibility and ESCA shifts. It seems that these parameters can be considered as pretty sensitive probes of the wave function quality. In this context it might be surprising that for certain properties even the lAM model is able to give reliable estimates. Nevertheless, in most cases one should take into account that the atoms are considerably modified by their molecular environment [47-50]. 

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