The asymmetric C-H 2 stretching mode of formaldehyde in water is reproduced well by the QM/MM-PHVA with minor frequency and intensity errors. Increasing the size of the QM subsystem results in a larger frequency error of 23 cm -1 and also larger but minor relative and absolute Raman intensity errors. In the symmetric C-H 2 stretching mode, the frequency error is slightly reduced from 13 cm -1 to 12 cm -1 . In contrast, the improvement of the C=O stretching mode is more substantial. Here the frequency error is lowered from 14 cm -1 to difference, but the relative errors are small in both systems, so it is not likely to be visible in a spectrum. The C-H 2 scissoring mode is well described in both systems but slightly worse in the formaldehyde-water cluster, while the C-H 2 rocking and wagging modes are reproduced better using the expanded QM subsystem. For the scissoring mode, the frequency error goes up from 0 cm -1 to 3 cm -1 , but intensities are slightly improved. In the rocking and wagging modes, the frequency errors are reduced from 10 cm -1 to 0 cm -1 and 13 cm -1 to 7 cm -1 , respectively, and the intensities of the rocking mode are also improved.