Magnetic properties of a diamagnetic gas in a resonance radiation field

An investigation is made of the change in the magnetic properties of a diamagnetic molecule (atom) induced by a resonance optical radiation field. Calculations are made for the 0→1 molecular transition in the presence of an external magnetostatic field. Expressions are derived for the magnetization and the magnetic susceptibility of the molecule, which depend nonlinearly on the light wave intensity, in the case of longitudinal and transverse directions of the external magnetic field with respect to the direction of propagation of the radiation. It is shown that the field-induced nonlinear magnetic susceptibility of a diamagnetic substance can change sign and increase considerably (by several orders of magnitude compared with the linear diamagnetic susceptibility). The field-induced nonlinear magnetization of the substance does not depend on its magnetic properties and is the same for diamagnetic and paramagnetic substances.