The nature of double scattering light from agueous solution of ion-association complex of selenium (IV)-I^-─rhodamine B system was studied. The spectral characteristics of the double scattering, the effective factors and optimum conditions of the reaction have been investigated. The relation between the intensity of double scattering light and the concentration of selenium (IV) by the double selenium (IV) was established. A New way for determination of trace amounts of selenium (IV) by the double scattering spectra was propsed . The mechanism of the reaction was also discuesed.

Key words: SPECTROPHOTOMETRY, SELENIUM, REACTION MECHANISM, IODIDE, SCATTERING SPECTRA, FLUOROSPECTROPHOTOMETRY, RHODAMINE B