Knight shift in small platinum particles

We have prepared small platinum particles on Si${\mathrm{O}}_2$ by a novel method, and observed the ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pt}$ nuclear magnetic resonance. The signals are extremely broad, ranging essentially from a field-to-frequency ratio $\frac{H_0}{{\nu }_0}=1.14\mathrm{}$ G/kHz (as in bulk Pt) to $\frac{H_0}{{\nu }_0}=1.10\mathrm{}$ G/kHz (which is zero shift by convention). We suggest that the latter value is characteristic for Pt nuclei in a metallic environment at or near a clean surface.