Is there a way to print the symmetry of each normal mode when performing a frequency calculation? I looked in the manual but did not find anything.
If not is there a tool to calculate the Irreps from the mode vectors given in the frequency output?
Symmetry is used to figure out whether or not each mode is IR and/or Raman active, and looking at the code it’s using irreps to do so, but the assignment of the actual irrep label is not done, so there’s no print level to change this (vibman_print is usually it). You can see all of this in FrqSYML.
If there is a (external) tool to do the assignment, I’m not aware of it, but have never looked.