Abstract
Recently, the research on calcium fluoride has been intensively carried out focusing on the window of vacuum ultraviolet applica-tion. Therefore it is important to investigate the properties of excimer grade (4N) molten calcium fluoride. The density and the surface tension of molten calcium fluoride have been mea-sured in the temperature range from 1690 to 1790K by an improved Archimedian method and a ring depressing technique, respectively. The density of the CaF_2 melt at the melting point was 2.594g/cm^3, which is equal to the result obtained by Shiraishi2), but the temperature coefficient of the density was dif-ferent from the results obtained by other investigators. The sur-face tension of molten calcium fluoride indicates a negative linear relationship with the melt temperature:γ(T)=442.4-0.0816×T(K) [10^<-3>N/m]. The surface tension measured using the ring depressing technique was larger then those results obtained by other techniques.
