Analytical expressions for the Morse potential parameters of diamond crystals have been derived. They contain the energy of sublimation, the compressibility and the lattice constant. Numerical calculations have been carried out for Si and Sn, and the results reflect fundamental properties of this potential. The obtained Morse potential parameters have been used for calculation of the anharmonic correlated effective potentials of these crystals in XAFS theory showing clearly anharmonic effects . .
