Analysis of X-ray Diffraction Pattern of Carbon by the Profile Fitting Method

Abstract

The profile fitting method using the least square refinement was applied for the determination of the lattice constants and crystallite sizes of carbon. Firstly, the diffraction profiles of carbon and silicon as an internal standard were decomposed to the Kai and Kα2 profiles by Rachinger's method and then, the peak positions, heights and half widths of the two profiles were estimated. Using the obtained profile parameters as initial values, the least square refinements by Simplex method and Gauss-Newton method were carried out and both of the results were compared. The Gauss-Newton method showed the better convergence performance than that of Simplex method from the viewpoint of the convergence speed and the final convergence point.