Neutron single crystal diffraction: techniques and applications in molecular systems

Abstract

Single crystal neutron diffraction is a powerful method for the investigation of molecular structure, and in many cases is found to be an excellent complement to X-ray diffraction. The ability of neutron diffraction to determine the position of the atomic nucleus, rather than the electron density, is key to its use in structural studies. Among other advantages, this lends the neutron the ability to determine accurately the positions (and displacement parameters) of light atoms. In the context of molecular systems, neutron diffraction is thus very well suited to the determination of hydrogen atom parameters, which are key to many applications in molecular structure determination, including hydrogen bonded systems, organometallic materials and in macromolecular structures.

This article briefly summarises some of the applications to which single crystal neutron diffraction has been put in the study of molecular structure, together with an account of the techniques and instrumentation used for these experiments. Particular account is taken of recent developments in instrumentation, and the new scientific applications that have resulted from these, along with a forward look to some of the exciting developments currently taking place in this field. These include instruments with dramatically enhanced detector arrays, other optimisations to improve count-rate and performance, the construction of new neutron sources and exciting new instruments being planned for these sources.