Another signature of hydrogen bonding

Previously I posted about how significant redshifts in the frequency of the O-H bond stretch can be a signature of hydrogen bonding. Furthermore, there is a fairly universal relationship between the frequency shift and the bond length and energy.

The graph above shows there is also a fairly universal relationship between the bond energy (horizontal scale) and the change in intensity of the O-H infrared absorption intensity, covering a factor of 200 fold variation in the energy. The details are summarised in this paper. The vertical scale is the bond energy calculated from the empirical relation −ΔH=12.2 ΔA^1/2 where ΔH is the enthalpy in kJ/mol and  ΔA is the change in intensity of the absorption line in units of 10⁻⁴ cm mmol⁻¹.