On the excitation of CH microwave lines

Abstract

Along with the very frequent occurrence of every CH 9 cm line inversion, CH radio observations also show the existence of antother almost universal characteristic of thes lines’s excitation: the overexcitation of the satellite F = 0→ 1 line. Attempts to explain this fact, by means of quite a wide sample of local and nonlocal models as presented here, failed when line overlap was not taken into account. As will be shown, the overlap of two components (F=2^+ → 1^- and F=1^+→1^-) of the ^2π_1/2 J=3/2→J=1/2 rotational transition leads to the above-mentioned satellite-line anomalies. The numerical results are in reasonable agreement with the observations, and the mechanism satisfies the requirement of universality.