COLLISIONAL COUPLING BETWEEN HYPERFINE AND STARK COMPONENTS OF MOLECULAR-SPECTRA

A theoretical treatment, based on a tensorial expansion of the scatter ing matrix, is presented for collisional coupling between hyperfine an d Stark components of molecular spectral lines. This treatment also de scribes the dependence of collisional broadening of well-resolved comp onents on F and M(F) quantum numbers. The case of molecules with a lar ge dipole moment is discussed in detail and simple selection rules are obtained for collisional coupling by using our treatment of the relax ation matrix within a perturbative expansion of the scattering matrix. The existing experimental results are explained.