Correlation between the total intensity under the infrared absorption band (integrated absorbance) and mean wavenumber of the absorption band.  This curve demonstrates for crystalline minerals a relationship between band intensity and wavenumber (which is related to the hydrogen bond distance) which has been previously well-established for water in solutions and glasses.

From:  Libowitzky E, Rossman GR (1997)  An IR absorption calibration for water in minerals.  American Mineralogist.