SIMBAD references

Absorption oscillator strengths for electronic transitions involving Rydberg states of the CH molecule, as well as photoionization cross sections for the different channels leading to the ground state of the cationic core, CH⁺, have been calculated with the molecular-adapted quantum defect (molecular quantum defect orbital (MQDO)) method. This molecule has been observed in the absorption spectra of comets, interstellar clouds, and stellar atmospheres. The results have been analyzed on the grounds of theoretical data found in the literature and by compliance with continuity across the ionization threshold. The use of the MQDO method as an alternative to ab initio methods, which, in spite of recent advances, still encounter serious difficulties in dealing with molecular Rydberg states of CH, is proposed.