Dipole moments expansion, property derivatives from

C. Property Derivatives from Expansion of the Dipole Moment... 

In the derivation of the molecular properties, which give rise to this effect, we have to take the spatial variation of the electric field vector into account and can thus not make the dipole approximation, contrary to the last section. This implies that we have to include a contribution from the interaction with the curl of the time-dependent electric-field, V xS r,t), to the expansion of the induced dipole moment of a molecule in Eq. (7.18). However, Maxwell s third equation, Eq. (2.37) relates the curl of the electric-field vector to the time derivative dB r,t)/dt of the magnetic induction and we can thus alternatively replace the spatial variation and expand the induced dipole moment instead in the electric field and the time derivative of the magnetic induction of a monochromatic wave (Buckingham, 1967) as... 

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