20 5 SUPPLEMENTARY NOTATION I COSATI CODES 18 SUBJECT TERMS (Continue on reverse of necessary and identify by block number) FIELD GROUP SUBGROUP ABSTRACT (Continue on revere if necessary and identify by block number) Measurements of the first order Raman spectrum in natural type Ila diamond for the temperature range of 293 K to 1850 K are presented. Both the Stokes and anti-Stokes components are analyzed for their intensity, Raman shift, and width variation with temperature. Optical pyrometry was used to make the temperature measurements, the results of which were independently confirmed by the Stokes to anti-Stokes intensity ratios. The shift and width variations with temperature are in general agreement with the molecular dynamics simulation of C. Z. Wang, C. T. Chan, and K. M. Ho whys. Rev. B, to be published)-, Heating of the samples to temperatures as high as 1850 K in vacuo could be pefo-ref -withodt any evience of polymorphic conversion to graphite, also in agreement with previous investigations. ,Our experimental first order Raman shifts, using units of cm-' and absolute temperature, are conveniently exprq'ssed as Av = aI7 2 + a 2 T + a 3 with the coefficients found to be-1.075 x 10-' cm-K-',-0.00777 cm-' IC, and 1'334.5 cm-, respectively.

No abstract

No abstract