Raman H-bond energies and pair volumes for water

Maximum values of the H-bond energies and H-bond pair volumes were determined from the OD-stretching Raman contour of HDO in water using, dispersion curves obtained from the temperature and pressure dependence of the intensities. The maximum H-bond DeltaE value is 5,100 +/- 500 cal/mol, and the maximum H-bond pair DeltaV is 1.4 cm(3)/mol. A minimum in the volume dispersion curve indicates that some H-bonds are strongly bent as the volume is decreased by pressure rise to approximate to 10 kbar at 28 degrees C. Similar effects of H-bond bending are observed from dispersion curves obtained from NaCl and NaBF4 in water. The main effect on liquid water of isothermal pressure rise to 10 kbar is to form H-bonds, both linear and bent, thus explaining freezing to ice VI.