In addition to the redshifts between QM/MM and MQC results, another difference is that the total amplitude of coupling to the OH stretch at the QM/MM level is significantly increased compared to MQC. Integrating the modulus squared of the Fourier transform between 2500 and 4000 cm -1 reveals that the coupling to the OH stretch is 8.6 times stronger in the QM/MM model compared to MQC. On the other hand, the coupling to the bend is comparable: between 1616 and 2500 cm -1 , the MQC integral is 1.9 times larger than QM/MM. The ratio of MQC:QM/MM bend intensity reduces to 1.1 if the second QM/MM peak is included by extending the lower integration limit to 1350 cm -1 .