This analysis shows that projecting out translation and rotation can substantially affect frequencies, IR intensities, and Raman intensities. Generally, the normal modes most affected are the low-frequency ones, while the high-frequency modes are unaffected. It is also noteworthy that the IR and Raman intensities are more sensitive than the frequencies. For example, for a normal mode in 1,3-butadiene in water, the difference was more than 50 % while the frequency only changed by about 3 cm -1 . Moreover, by including solvent molecules in the QM subsystem, the pseudo-translational and pseudo-rotational contributions are affecting more normal modes compared to systems without solvent molecules. In the systems where only the solute is in the QM subsystem, these contributions are visible in, at most, nine of the lowest-frequency modes. Clearly, the impact of projection can be substantial, and since it is also unfounded, a better approach to eliminating the problematic modes is to quantify the pseudo-translational and pseudo-rotational contributions and remove the modes with contributions higher than a threshold.