Reweighting entropy (RE), is a measure of the reliability of the RPM. We have previously shown that when RE is greater than 0.3 in the MsTP calculations, the extrapolation process is reliable. When it is below 0.3, large biases may reside in the free energy profile. As shown in Fig. , the free energy profile under the DFT level is reliable when the CV is smaller than 0.8 Å. When the CV is greater than 0.8 Å, RE plunges. This is the consequence of the large difference in the preferred structures under these two Hamiltonians, i.e. SQM and DFT.