How are the normal modes vectors printed on the Q-chem output is related to eigen vectors of projected mass weighted hessian that can be printed using vibman_print. I was trying to figure this out but unable to do that.
What’s in the usual output should be normal-to-Cartesian vectors, i.e., they have been un-mass-weighted.
You can find detailed explanations in ezFCF manual:
https://iopenshell.usc.edu/downloads/ezFCF_manual.pdf
Note that you can also set VIBMAN_PRINT = 4 to get Q-Chem to print the Hessian in both Cartesian and mass-weighted Cartesian coordinates, along with some other quantities that are ordinarily suppressed in the output. VIBMAN_PRINT = 6 will print even more info.