DOWNSHIFT OF RAMAN PEAK IN DIAMOND POWDERS

Results are presented on the influence of the size of diamond powders and the laser power on the main Raman line. These results show conclus ively that there is a consistent and systematic, reversible, downshift with both decrease of powder size, and increase of power. The shift c an be explained by local heating of about 500 degrees C in the extreme case. Its significance applies to interpretation of the alleged;''dow nshifting'' of the 1332 cm(-1) Line in all diamond research. In the fu ture, the grain size, the thermal contact, and the beam power must be carefully monitored in reporting and interpreting any frequency shifts .