We measured the infrared vibrational properties of bulk and nanoparticle WS2 in order to investigate the structure-property relations in these novel materials. In addition to the symmetry-breaking effects of local strain, nanoparticle curvature modifies the local charging environment of the bulk material. Performing a charge analysis on the \emph{xy}-polarized E1u vibrational mode, we find an approximate 1.5:1 intralayer charge difference between the layered 2H material and inorganic fullerene-like (IF) nanoparticles. This effective charge difference may impact the solid-state lubrication properties of nanoscale metal dichalcogenides.
@article{arxiv.cond-mat/0601107,
title = {Dynamics of Bulk vs. Nanoscale WS_2: Local Strain and Charging Effects},
author = {R. D. Luttrell and S. Brown and J. Cao and J. L. Musfeldt and R. Rosentsveig and R. Tenne},
journal= {arXiv preprint arXiv:cond-mat/0601107},
year = {2009}
}