A VERY HIGH-RESOLUTION SURVEY OF INTERSTELLAR CH AND CH+

We report the results of a survey at very high spectral resolution of interstellar CH and CH+ in diffuse clouds toward 20 bright stars, and medium-resolution observations to determine radial velocities. The hig h-resolution observations [(lambda/delta lambda) similar to 500,000] r esolve all the CH+ and all the CH lines. Most of the CH lines show mul tiple overlapping components at this resolution. It is often possible to associate a weak broad CH component with a CH+ component of similar radial velocity and width. The implications of these results for CH a nd CH+ formation scenarios are discussed.