Stopping anisotropy in molecular chains

Recently, we have addressed the effects of overall shape upon the electronic response of isolated molecules and nanoclusters, with particular emphasis on the mean excitation energy. Here, we consider the relationship between gross molecular shape and mean excitation energy anisotropy for very long objects. In particular we compare results for elongated ellipsoids and a string of particles. We find the latter model gives a better prediction of stopping power anisotropies of isolated long molecules