CHAPTER 2 The Xenon Chemical Shift and Chemical Shift Anisotropy CYNTHIA J. JAMESON University of Illinois, Chicago, USA Email: cjjames@uic.edu 2.1 Scope and Emphasis This review will focus on (a) understanding observed Xe chemical shifts at an electronic structural level and (b) using that level of understanding to deduce what the observed Xe chemical shift is telling us about the physical system of interest. The goal is to use the theoretical understanding of the observations in model systems in order to interpret more general Xe observations in complex systems, such as those mentioned in extensive reviews by Fraissard in this book and elsewhere. Hyperpolarized Xe uniquely permits the observation of the Xe chemical shift under conditions that are in the limit of no Xe–Xe interactions. Thus, we discuss ‘‘a single Xe atom’’ as a probe of physical systems separately. On the other hand, in observations of the Xe chemical shift under variable-loading thermally polarized Xe conditions, the anisotropy of the inner spaces becomes more obvious when Xe–Xe interactions dominate the intermolecular Xe shift tensor. We use first principles calculations to make predictions for static geometries and grand canonical Monte Carlo (GCMC) simulations and molecular dynamics (MD) simulations to do the averaging that makes possible predictions of a general nature and comparison with specific experimental observations. In this chapter we limit interpretation to systems which have well-characterized New Developments in NMR No. 4 Hyperpolarized Xenon-129 Magnetic Resonance: Concepts, Production, Techniques and Applications Edited by Thomas Meersmann and Eike Brunner r The Royal Society of Chemistry 2015 Published by the Royal Society of Chemistry, www.rsc.org 16