Polarizabilities of atoms and molecules, new insights into an old subject

Abstract

The importance of electric polarizabilities is discussed in detail. Emphasis is given not only to the dipole–dipole polarizability α ̂ , but also to the dipole–quadrupole, dipole–octopole and quadrupole–quadrupole polarizabilities Â, Ê, and Ĉ, respectively, as examples for the higher-order polarizabilities. In the case of the nonlinear polarizabilities we concentrate on the second hyperpolarizability γ ̂ and the quadrupole–dipole–dipole polarizability B̂. New experimental techniques such as the asymmetric white-light interferometry, atomic–beam interferometry, electric field deflection techniques, and collision-induced spectroscopy are discussed. Recent experimental and theoretical results are presented for the frequency, density, and temperature dependence of the polarizabilities. Special emphasis is given to new results concerning the frequency dependences of the mean dipole-polarizability of molecular iodine and of the polarizability anisotropy of carbon dioxide in the gas phase. An outlook is given for future work devoted to polarizabilities.