The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by software engineers and scientists at the ISIS Neutron and Muon Facility and the Oak Ridge National Laboratory. The objectives, functionality and novel design aspects of Mantid are described.

Electrical transport through molecules has been much studied since it was proposed that individual molecules might behave like basic electronic devices, and intriguing single-molecule electronic effects have been demonstrated. But because transport properties are sensitive to structural variations on the atomic scale, further progress calls for detailed knowledge of how the functional properties of molecules depend on structural features. The characterization of two-terminal structures has become increasingly robust and reproducible, and for some systems detailed structural characterization of molecules on electrodes or insulators is available. Here we present scanning tunnelling microscopy observations and classical electrostatic and quantum mechanical modelling results that show that the electrostatic field emanating from a fixed point charge regulates the conductivity of nearby substrate-bound molecules. We find that the onset of molecular conduction is shifted by changing the charge state of a silicon surface atom, or by varying the spatial relationship between the molecule and that charged centre. Because the shifting results in conductivity changes of substantial magnitude, these effects are easily observed at room temperature.

The nanoscale structuring of molecules on silicon surfaces is one approach for combining the tuneable properties of chemical species with the functionality of semiconductor materials. In this study, we report on the growth characteristics of trimethylene sulfide (TMS) on p- and n-type H−Si(100)-2 × 1. The nanostructures formed by TMS on either surface are indistinguishable by scanning tunneling microscopy (STM). However, high-resolution electron energy loss spectroscopy (HREELS) and modeling by density functional theory indicate that the molecular attachment mechanism differs with dopant type. Our results show that TMS adds to a surface silicon dangling bond through the formation of a Si−S bond on p-type silicon and through the formation of a Si−C bond on n-type silicon. In both cases, the added TMS undergoes ring opening following covalent bond formation with the surface. The different ring-opened radicals are able to abstract a hydrogen atom from one of two neighboring silicon dimers. The overall reaction produces TMS-derived nanostructures that grow via a square-wave pattern on the neighboring edges of two dimer rows.