Structure factor of liquid n -butanol at room temperature

The structure factor of deuterated liquid n-butanol (C4D10O) has been investigated by neutron diffraction with the aim of exploring the physical nature of the observed prepeak. The experiment was conducted using two neutron diffractometers: D16 to get a detailed structure factor in the low-Q range, and D4 for a high precision structure factor and proper normalization. In this way a total structure factor was determined covering an extended Q-range from 0.04 to 23.4 A−1. A molecular dynamics simulation using the general all-atom ab initio force field COMPASS was also carried out. The agreement between experimental and simulated data is very good, giving a plausible interpretation of the origin of the pre-peak observed at 0.6 A−1 as coming from the intermolecular ordering in the liquid.