Experimental study on the forced Rayleigh scattering method using CO ₂ laser (2nd report, investigation of error factors due to free-surface-heating technique)

The purpose of this study is to develop a practical forced Rayleigh scattering apparatus applicable to a wide range of substances and conditions. In the present paper we investigated error factors due to free-surface-heating technique. The error factors we considered here are; 1) effect of two-dimensional heat conduction due to surface-heating, 2) effect of heating duration time. These error factors hinder the one-dimensional heat conduction or optical condition assumed in the basic theory. As a result, it has been found that the individual error is apparently increased byinterference with the effect of scattered light. We have attempted to apply new analysis in order to correct the error. Finally, we have estimated the accuracy for the thermal diffusivity of toluene water and molten carbonates measured by this method.