RESOLUTION OF COUPLED EQUATIONS TO STUDY PERTURBATIOSOINS AND PREDICATIONS: APPLICATION TO THE $\Pi_{u}$ STATES OF $N_{2}$

Abstract

When several states are coupled by electrostatic or spin-orbit interaction, it is possible to solve the coupled equations of the problem. The energy levels (and eventually their widths) are obtained by studying the change phase of the solution in an open channel. This channel is either the channel of predissociation, or an artificial channel in the case of perturbations. An example of the perturbations of the $C^{3}\Pi_{u}$ state in the $N_{2}$ molecule by the ${C^{\prime}}{^{3}\Pi_{u}}$ state is treated. The level shift due to the continuum is shown. The predissociation of the $\nu = 3$ level of the $b^{1}\Pi_{u}$ state is interpreted in terms of indirect predissociation involving the C and ${C^{\prime}}{^{3}\Pi_{u}}$ states.