Left panel: ratio of the non-zero rate coefficients (denoted as q) from the asymptotic LCAO and free electron model calculations, as a function of the transition energy, i.e. the difference between the energy of the final and initial state (for the states in Table 1). Right panel: rate coefficients (q) from the extended asymptotic LCAO and free electron model calculations, as a function of the excitation energy of the initial state (for states up to 7.645 eV). For both panels, the rates are for the excitation and ion-pair production processes at 6000 K.