In the cases of pyridine in methanol and 1,3-butadiene in water, the pseudo-translational and pseudo-rotational contributions for all modes except the six lowest-frequency modes go up to around 3 %. The projection affects frequencies, IR intensities, and Raman intensities for both systems. The maximum frequency difference is around 3 cm -1 , while the relative intensity differences are higher for pyridine in methanol (up to 76 % for Raman and 68 % for IR) than for 1,3-butadiene in water (up to 57 % for Raman and 52 % for IR). The absolute differences are also substantial for the aforementioned modes with high relative differences, so we expect to see a noticeable difference in the spectra for these systems.