The validation data on MOF-303 were used to show the technique's applicability to a sample other than CALF-20. Also, measurements at the specific relative humidity conditions shown in Figure help in understanding the error in FT-CSFR as a function of isotherm slope since MOF-303 has a steep slope at lower RH values with a sharp step around 12% RH and a more shallow uptake at higher RH. Additionally, the 26% RH run on MOF-303 was collected on a separate CSFR instrument from the other data to ensure consistency in the method between instruments. Control data (no adsorbent present) was collected using sine waves and FT-CSFR to validate the technique further. Figure shows the Bode plots of amplitude ratio (out/in) vs. frequency from each of these experiments. In Figure , the diffusion data for CO2 on CALF-20 show that FT-CSFR is sensitive to the adsorption mechanism and provides the same inflected curve shape as previously reported for this system, which can be described by a linear driving force (LDF) model. The technique also shows repeatability, as indicated by the triplicate measurements in Figure . The corresponding rates calculated from these data are shown in Table . Figure shows H2O diffusion data at 5% and 40% RH, also previously reported for this system. The diffusion of water in CALF-20 shows micropore diffusion control, and the rates agree well (within a factor of 3) with those previously reported, as seen in Table . Additionally, these results show that the humidity induced  to  polymorphism in CALF-20 does not influence the diffusion of H2O in the pores.