The as-prepared Pt4Ge/alumina sample was probed both before (Fig. ) and after (Fig. ) the 750 K heating used to remove residual H and Cl from clusters. For the unheated clusters, the initial Pt and Ge intensities were small, increasing as the adsorbed H and Cl were sputtered, exposing underlying Pt and Ge atoms, and then decreasing slightly at long exposures as Pt and Ge were lost to sputtering. For the sample probed after 750 K heating (Fig. ), the initial Pt and Ge intensities were similar to the maximum intensities seen for the unheated sample, i.e., removing the adsorbates by heating vs. He + sputtering had similar effects. The initial Pt ISS signal for the heated Pt4Ge/alumina sample was ~37% smaller than the signal observed for heated Pt4/alumina, presumably reflecting some shadowing or blocking of He + scattering from Pt by the Ge atom. The 37% lower Pt ISS intensity was quite similar to the 41% lower total adsorbed C2D4 measured in the initial Pt4Ge/alumina TPD (Tables and). For Pt4Ge/alumina samples that were heated to 750 K then subjected to 1 or 6 TPD runs (Fig. and), the Pt intensities were attenuated compared to the heated sample, as expected from the fact that some carbon deposition occurred.