On the structure function of liquid alcohols at small wave numbers and signature of hydrogen-bonded clusters in the liquid state

Abstract

It has been known for long that the X-ray diffraction data for structure functions of liquid alcohols exhibit a characteristic pre-peak at small wave numbers ( Q ∼ 0.8 A ̊ −1 ). The recent time of flight neutron diffraction data on deuterated isopropanol too exhibit a similar pre-peak at about the same wave number. The carefully studied reactor neutron data on deuterated methanol also show similar pre-peaks at room and elevated temperatures. It is shown on the basis of the model analysis that these pre-peaks could be related to dominant hydrogen-bonded molecular clusters such as “hexamers” in liquid state.