Connection between the nuclear electric shielding tensor and the infrared intensity

The integrated IR intensity can be directly related to the electric shielding tensor of the nuclei in a molecule. This allows us to measure, by IR spectroscopy, the effective electric field at the nuclei of a molecule immersed in an external electric field. Relations exist with the dynamic polarizability and the magnetizability, which implies the possibility of a unified treatment of electric and magnetic second-order properties.