Neutron single crystal diffuse scattering from D2O ice Ih has been mea
sured over large regions of reciprocal space on the SXD diffractometer
at ISIS. This scattering shows additional features to those predicted
solely on the basis of deuteron disorder within the Bernal-Fowler rul
es. A reverse Monte Carlo modelling technique has been developed for u
se with single crystal diffuse scattering, and has allowed extensive i
nformation to be obtained about the structure of ice Ih.