The structure of liquid iodomethane, CH(3)I/CD(3)I

An x-ray diffraction measurement has been performed on liquid iodomethane using the BL04B2 beamline at the SPring-8 synchrotron radiation facility (Japan). The corrected structure factor, together with the results of an earlier neutron diffraction study, has been interpreted by means of reverse Monte Carlo modelling. This approach provides large structural models, containing thousands of atoms that are consistent with the experimental data within their uncertainties. From these models, partial structure factors and radial distribution functions were calculated. It is demonstrated that, for a satisfactory description of the intermolecular correlations, the presence of x-ray data is vital. Orientational correlations between neighbouring molecules have been found to be much better defined than if they were due to excluded volume effects only.