The first-order Raman spectrum of diamond has been measured in a diamond-anvil cell up to 27 GPa. The fundamental phonon line varies linearly in pressure with a shift of 2.87 ${\mathrm{cm}}^{\mathrm{-}1}$/GPa. This line appears to be an excellent pressure-calibration standard as an alternate to the ruby pressure scale.

• Received 22 April 1985

DOI:https://doi.org/10.1103/PhysRevB.32.1423