It is insightful to compare these calculations with the equivalent static calculations using PDielec shown in Figure (a). Firstly both methods show similar overall trends, a direct comparison is made difficult because of the larger spectral linewidths that are observed in the dynamic calculations, with the spectrum showing similar trends in both sets of calculations, for instance Form III shows very little absorption below 110 cm -1 using either method while Form II shows the lowest absorption and highest intensity mode in both. The integrated absorptions are different between the two calculations with the integrated absorption of the static calculations being at least half that of the dynamic calculations for all forms.