We present SOFIA/GREAT [CII] observations of nearby clouds near the lines of sight towards to quasars. These clouds have been studied in various tracers, originally as part of an extensive mm-wave absorption study by Lucas, Pety and Liszt. From these studies, the clouds were categorized as diffuse clouds and the small scale structure visible in CO was interpreted as chemical variations inside the clouds. The fact that SOFIA/GREAT failed to detect [CII] at the predicted intensity by at least a factor of 7 is in contradiction with this interpretation. The observed upper limit on [CII] and the 12CO and 13CO low-J line intensities rather are consistent with the clouds being moderately dense molecular cloudlets embedded in an average Galactic FUV field.
This work has been part of the recently finished PhD thesis of Christian Glück and has been accepted for publication in A&A.