Towards a more detailed understanding of the OH-stretching bands of H-bonded liquids

The stretching mode of OH-groups with a proton donor function of an alcohol associating to singly hydrogen-bonded dimers is investigated in the liquid phase. Spectral holes with a frequency spacing of ≈35 cm−1 in the fundamental OH-transition and of ≈45 cm−1 in the vibrationally excited state absorption are determined. This gives evidence for combination tones with the bending vibration of the hydrogen bridge bond governing the dynamics and the shape of the proton donor OH-stretching band.