Polarisability and Its Anisotropy

Polarisability relates the dipole moment of a molecule linearly to an applied electric field 

A sequence of calculations can be performed with various applied electric fields in which the dipole moment of the molecule is evaluated, as described above. The 3x3 polarisability tensor, can therefore be constructed. 

For the linear response of the dipole to an electric field, this calculation is fairly straightforward. However, the dipole can also be calculated for a range of magnitudes of applied field to obtain higher order hyperpolarisabilities such as j . 

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