Diamagnetic and paramagnetic contributions

Each of these contributions looks suspicious. Indeed, the diamagnetic contribution explicitly depends on the choice of origin R of vector potential A through roy = ry — R, see (12.65). Similarly, the paramagnetic contribution also depends on choice through Loy and (12.65). We have already stressed the practical importance of the choice of in Appendix G. Since both contributions depend on the choice, they separately cannot have any physical significance. 

Is it possible that the sum of the two contributions is invariant with respect to choice of R7 Yes, it is The invariance has fortunately been proved.This is good, because any measurable quantity cannot depend on an arbitrary choice of the origin of the coordinate system. 

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Another interesting point is to be presented in relation to chemical shift evaluations. From the directly-measured spin-rotation constant of POF3, diamagnetic and paramagnetic contributions to phosphorus chemical shifts were estimated (ca. +1000 and —640 p.p.m.). Extended to H3P04, which is the commonly accepted reference compound, this gives about 320 p.p.m. for the absolute 31P chemical shift.a999,9)... 

Chemical shifts, as treated by Ramsey (113), are comprised of separate diamagnetic and paramagnetic contributions. The diamagnetic term was considered to arise from the response of the extranuclear electrons to the external magnetic field and had been given earlier by Lamb (65) as... 

The third-rank diamagnetic and paramagnetic contributions to electric field dependent magnetic susceptibility and nuclear magnetic shielding, to first order in... 

We recall that the partition into diamagnetic and paramagnetic contributions to the molecular properties is not unique and, to some extent, linphysical. For instance, in the case of a static uniform magnetic field, the resolutions of Eqn. (93) into (92) and (91) and of (99) into (97) and (98) stem from the choice... 

The resulting gauge independent expressions for the local diamagnetic and paramagnetic contributions to the screening of nucleus A, where a and P are labels for the cartesian components x,y and z, are given by ... 

Table 15. Diamagnetic and paramagnetic contributions, (r and to the germanium nuclear magnetic shielding constants (rand their analyses into core and valence MO contributions (in ppm)... 

By analogy with equation (20), it is expedient to split the polarizabilities and hyperpolarizabilities into diamagnetic and paramagnetic contributions. 

Diamagnetic and Paramagnetic Contributions The Ramsey Theory of NMR Spin-Spin Conpling Constants (4(g))... 

Using this result, the nuclear spin-spin coupling constant is calculated as the sum of the diamagnetic and paramagnetic contributions ... 

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