Optical Properties of Small Gold Particles

The optical absorption of dispersions of gold particles is studied as a function of particle size, temperature, and method of preparation. The absorption spectra for gold sols in glass and water with small spread in particle size are compared to spectra calculated from Mie theory and the most reliable of recently measured optical constants of gold. The comparisons indicate that the real part of the dielectric constant e1 for particles from 85 to 200 A in diameter is the same as for bulk gold, and that the imaginary part e2 is similar for particles and bulk, although some discrepancies exist. Gold sols in glass have optical properties closer to bulk gold than sols in water, probably because of defects and adsorbed material on the particles in water. Between wavelengths of about 0.40 and 0.45 μ the optical properties of the particles in glass are unchanged down to particles containing very few atoms. The optical absorption peak at 0.525 μ is unaffected by particle size down to a particle diameter of about 8...

[1]  C. Fragstein,et al.  Eine neue, einfache, polarimetrische Methode zur Bestimmung der optischen Konstanten von Metallen , 1963 .

[2]  H. Ehrenreich,et al.  Optical Properties of Ag and Cu , 1962 .

[3]  F. Abelès.  Propriétés optiques d'alliages Au-Ni , 1962 .

[4]  Margie K. Reser,et al.  Symposium on nucleation and crystallization in glasses and Melts , 1962 .

[5]  M. Otter,et al.  Optische Konstanten massiver Metalle , 1961 .

[6]  W. Doyle.  Coagulation, Optical Absorption and Photoconductivity of Colloid Centres in Alkali Halides , 1960 .

[7]  R. Maurer.  Effect of Catalyst Size in Heterogeneous Nucleation , 1959 .

[8]  W. Doyle.  Absorption of Light by Colloids in Alkali Halide Crystals , 1958 .

[9]  W. Hampe.  Beitrag zur Deutung der anomalen optischen Eigenschaften feinstteiliger Metallkolloide in großer Konzentration , 1958 .

[10]  C. Fragstein,et al.  Über die Anomalie der optischen Konstanten , 1958 .

[11]  Robert D. Maurer,et al.  Nucleation and Growth in a Photosensitive Glass , 1958 .

[12]  H. V. Hulst.  Light Scattering by Small Particles , 1957 .

[13]  M. De.  Handbuch der Physik , 1957 .

[14]  H. Y. Fan,et al.  Infra-red Absorption in Semiconductors , 1956 .

[15]  L. Schulz,et al.  The Optical Constants of Silver, Gold, Copper, and Aluminum. I. The Absorption Coefficient k , 1954 .

[16]  B. Seraphin.  Ultraviolettabsorption kolloidaler Goldlösungen , 1952 .

[17]  J. Hillier,et al.  A study of the nucleation and growth processes in the synthesis of colloidal gold , 1951 .

[18]  R. Kretzmann.  Über optische Konstanten dicker Metallschichten im Sichtbaren und nahen Ultrarot , 1940 .

[19]  F. Goos.  Die optischen Konstanten dünner Goldschichten aus Durchlässigkeits- und Reflexionsmessungen von Ultrarot bis Ultraviolett , 1937 .

[20]  R. Gans,et al.  Über die Form ultramikroskopischer Goldteilchen , 1912 .

[21]  W. Steubing.  Über die optischen Eigenschaften kolloidaler Goldlösungen , 2022 .

[22]  G. Mie.  Beiträge zur Optik trüber Medien, speziell kolloidaler Metallösungen , 1908 .