  Following a demonstration of how neutron diffraction with polarization
analysis may be applied for the accurate determination of the coherent static
structure factor of disordered materials containing substantial amounts of
proton nuclei (Temleitner et al., Phys. Rev. B 92, 014201, 2015), we now focus
on the incoherent scattering. Incoherent contributions are responsible for the
great difficulties while processing standard (non-polarized) neutron
diffraction data from hydrogenous materials, hence the importance of the issue.
Here we report incoherent scattering intensities for liquid acetone,
cyclohexane, methanol and water, as function of the $^1$H/H ratio. The
incoherent intensities are determined directly by polarized neutron
diffraction. This way, possible variations of the incoherent background due to
the changing chemical environment may be monitored. In addition, for some of
the water samples, incoherent intensities as a function of the wavelength of
the incident neutron beam (at 0.4, 0.5 and 0.8 \AA ) have also been measured.
It is found that in each case, the incoherent intensity can be described by a
single Gaussian function, within statistical errors. The (full) width (at half
maximum) of the Gaussians clearly depends on the applied wavelength. On the
other hand, the different bonding environments of hydrogen atoms do not seem to
affect the width of the Gaussian.
