Optical absorption of matrix isolated Si and Ge clusters

Abstract

Optical absorption spectra are reported for Si, Ge and SiGe clusters. The samples were prepared by the simultaneous condensation of rare gas and Si or Ge vapor onto a liquid helium temperature substrate. The dependence of the strength of individual absorption lines on the vapor/argon ratio allowed a tentative assignment of spectral features to one, two, three and four atom clusters. Empirical, extended Huckel calculations were made and, where meaningful, are compared with experiment.