Temperature variation of the Raman spectrum of topaz

Abstract

The temperature variation of the frequency shifts of the intense Raman lines of topaz has been investigated over the range of temperature from 30°C. to 450°C., using the λ2536 ÅU radiation of the mercury arc as the exciter. From the observed variation, values of x(=-1/v̅ dv̅/dT) have been calculated for the lines 241, 270, 289, 458, 522, 927, 985 and 3643 cm.^-1 In the case of the first five lines, ξ increases with temperature, while for the rest, ξ decreases with temperature. Unlike the case of calcite and quartz the absolute values of ξ for the different Raman lines of topaz do not show wide variations. The temperature variation of the width of the 458 cm.^-1 line has also been measured. The width to this line is found to increase proportional to the square root of the absolute temperature.