https://doi.org/10.1351/goldbook.08592
Influence of the linear term, \(\Sigma_{k} (\partial \boldsymbol{\mu}/\partial Q_{k}) Q_{k}\), in the expansion of the electric dipole moment. \(Q\) is the normal coordinate.
Note:
Electrical harmonicity should not be confused with mechanical harmonicity.
Electrical harmonicity should not be confused with mechanical harmonicity.