ANOMALOUS FREQUENCY AND TEMPERATURE DEPENDENCE OF THE OPTICAL ABSORPTION OF SMALL GOLD PARTICLES

U. Kreibig

Size effects have been studied in Au particles of various sizes (102 to 105 atoms/particle), which were prepared in a glass matrix. Absorption measurements at 300 K and 1.5 K in the spectral region from 0.5 to 4.2 eV revealed three effects, when the particle size was reduced : (i) The spherical surface plasmon band is broadened ; the imaginary part of the dielectric constant of the particle material increases. (ii) The temperature dependence of the plasmon band goes to zero. (iii) The interband transition threshold is shifted to lower energies and the slope of the edge is diminished. Effects (i) and (ii) can be explained by assuming discrete electron energy levels, effect (iii) points to lattice parameter changes and/or an increase of indirect transitions.

Domaines: Articles anciens

U. Kreibig. ANOMALOUS FREQUENCY AND TEMPERATURE DEPENDENCE OF THE OPTICAL ABSORPTION OF SMALL GOLD PARTICLES. Journal de Physique Colloques, 1977, 38 (C2), pp.C2-97-C2-103. ⟨10.1051/jphyscol:1977220⟩. ⟨jpa-00217059⟩