Electro-optics of molecules

The natural vibrations and electro-optics of diatomic molecules are considered in the framework of the perturbation theory. The energy of anharmonic vibrations and the matrix of a dipole moment function are determined with allowance made only for nonzero perturbation contributions. In particular, the case of strong electro-optical anharmonicity of diatomic molecules (i.e., the situation where the dipole moment function significantly deviates from linear behavior) is analyzed in the second order of the perturbation theory. Within tie introduced formalism of polynomials of the quantum numbers, the perturbation theory is extended to polyatomic molecules and expressions for the matrix elements of the dipole moment are derived in explicit form with due regard for the vibrational quantum numbers. (C) 2004 MAIK "Nauka/Interperiodica".