Raman Effect in Diamond

Abstract

FROM many points of view diamond is a crystal of supreme interest, and it is remarkable that, though more than two years have elapsed since the discovery of the Raman effect, no attempt appears to have been made so far to study the scattering of light in this substance. I have found that quite a small diamond (half carat size) suffices to photograph the Raman spectrum of crystalline carbon. Each of the mercury lines 4046.6 A. and 4358.3 A. excites a single Raman line of remarkable sharpness and intensity (Fig. 1, marked with arrows); the wave-number shifts are 1331 cm.⁻¹ and 1333 cm.⁻¹ respectively, in pleasing agreement with the wave-number 1333 cm.⁻¹ of the Rest-strahlen frequency of diamond (Nernst and Lindemann; Z. Electro-Chemie, 17, 822; 1911). The sharpness of the line is to be expected in view of the known perfection of the crystal, according to the ideas of Sir C. V. Raman (Faraday Society's Discussion, Bristol meeting). The brightness of the line is also not surprising in view of the ease with which organic substances generally give the Raman effect. Experiment shows that the line is strongly polarised.