In Figure , we examine the effects of adding solvent molecules to the QM subsystem by comparing calculations on formaldehyde in water with and without two water molecules in the QM subsystem. In the following and in Figure , the latter is referred to as the formaldehyde-water cluster in water. The results for formaldehyde in water are consistent with the other solute-solvent systems presented in Figure . Specifically, pseudo-translational and pseudo-rotational contributions are observed only in the six lowestfrequency modes. For all other normal modes, the frequency errors are minimal, with the highest error being in normal mode 5, which exhibits a frequency error of around 1 cm -1 .