The internal strain parameter of diamond from synchrotron radiation measurements

The internal strain parameter of diamond has been found from the uniaxial stress dependence of the integrated intensity of the forbidden 006 reflection. Synchrotron radiation from the storage ring DORIS-HASYLAB was conditioned by a gold mirror to provide 006 and 008 reflections from the sample. Integrated intensities was recorded to a bond-bending parameter xi =0.125+or-0.020. This value is in accord with two recent theoretical values based on a bond-charge model and on an ab initio pseudopotential calculation.