THE VIBRATIONAL STARK-EFFECT

Expressions for the frequency and intensity of the fundamental-vibrational transitions of a polyatomic molecule in the presence of a uniform or nonuniform electric field are reported. They have been developed on the basis of perturbation theory and take into account, individually, first-order electrical and mechanical anharmonicity. They are more general than previously-used expressions, since terms which are quadratic in the field strength are included. As an example of their use and of their interpretative capability, they are applied to CO.