Ionic force field of vibrational spectra of symmetrical hydrogen bonds

The ionic force field for analysis of the vibrational spectra of symmetrical hydrogen bonds, X–H–X, is described. The force field has a stretching force constant K and a force constant kc derived from the Coulombic force. One characteristic of this force field is that the frequency of the symmetric stretching vibration, νs, can be calculated from the values observed for out-of-plane bending and antisymmetric stretching bands of X–H–X. The agreement between the calculated and observed frequencies of the νs is excellent. The νs vibrations are treated as intermolecular vibrations such as those of carboxylic acid dimers.