The relation between column densities of interstellar OH and CH molecules

We present a new, close relation between column densities of OH and CH molecules based on 16 translucent sightlines (six of them new) and confirm the theoretical oscillator strengths of the OH A–X transitions at 3078 and 3082 \AA (0.00105, 0.000648) and CH B–X transitions at 3886 and 3890 \AA, (0.00320, 0.00210), respectively. We also report no difference between observed and previously modelled abundances of the OH molecule.