Accession Number:

ADA295675

Title:

Dicarbocyanine Dyes in Methanol Solution Probed by Rayleigh and Hyper-Rayleigh Light Scattering.

Descriptive Note:

Technical rept.,

Corporate Author:

NEBRASKA UNIV LINCOLN DEPT OF CHEMISTRY

Personal Author(s):

Report Date:

1995-06-30

Pagination or Media Count:

25.0

Abstract:

The hyper-Rayleigh scattering HRS intensity of two symmetric carbocyanine dyes 1122DEDC and 1144DEDC in methanol is measured as a function of dye concentration. These dye molecules at equilibrium show no permanent dipole moment. The low concentration data showing the HRS intensity is proportional to the dye concentration are used to determine the first order hyperpolarizability for each of these dyes. However, above concentration rhosub b 0.1 x 10exp -3 M, the HRS intensity shows an anomalous concentration dependence. Above rhosub b, the HRS shows a saturation behaviour and even decreases with increasing concentration at high dye concentration. At lowest concentration, the depolarization ratio obtained is consistent with that expected for molecules with Csub 2v symmetry. As the dye concentration increases, the depolarization ratio also increases rapidly but the increase quickly saturates as concentration exceeds rho sub b. The concentration dependence of the HRS intensity and depolarization ratio are interpreted as due to formation of molecular aggregrates. The depolarized Rayleigh scattering DRS intensity is also measured as a function of dye concentration. The result of DRS corroborates well that found of HRS. jg

Subject Categories:

  • Coatings, Colorants and Finishes
  • Organic Chemistry
  • Physical Chemistry
  • Optics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE